09:00:32 Alright so I'm going to just give a brief overview before we get started with this discussion and in doing so I'm just gonna share my screen.
09:00:44 Hopefully everyone can see that.
09:00:48 So it's just that just a few slides that I want to show, I won't bother going full screen here.
09:00:53 So, there are four meetings of our particular working group, and I'll say quotations climate applications climates just use loosely as a word for really thinking about staircases as they relate to the atmosphere and ocean or, more generally atmospheres
09:01:14 and the ocean. So today we're going to talk about PD staircases on Jupiter, and then the following three weeks they will all be oceanographic related.
09:01:23 Every 20 seconds. Now we'll have a discussion on staircases and poor oceans, due to isolation interactions. On March, 1, we will talk about staircases that have observed but not necessarily understood.
09:01:37 For example, and not directly linked to double diffuse of processes, but perhaps related to turbulence generation, or at least. They've been affected somehow by trigger emotions.
09:01:47 And finally, the, This one's really an ambitious goal, we're going to think about how we might take what we've learned about staircases in the ocean. And somehow, what do we need in order to take these concepts and apply them to parameter ization in general
09:02:03 circulation models. So that's the overview for the next four weeks in each of the discussions in the working group.
09:02:12 The plan is we'll start off with some short talks. And these are going to be recorded so I'm separately recording on my machine and Kitt is recording them.
09:02:21 Following the talks, which should go on for maybe half hour to 45 minutes, we'll have an open discussion and questions at this point it kind of depends on what people are thinking we could turn off the recording or keep recording.
09:02:36 But generally the plan by default will be we will not record that so that these discussions can be quite frank, if people want them to be about an hour we'll take a break and again depending on how things are going.
09:02:48 We may decide to that point to go into breakout rooms.
09:02:51 I will set up the breakout rooms so that you can choose which room you want to go into, you won't be assigned to go into a room you can choose where you want to go.
09:03:00 And you can actually freely walk out of a room and go to another room if you like.
09:03:05 And we will then leave time at the end, so that we get out of the breakout rooms we all meet together once again in this forum and have an open discussion, reporting on what was discussed in the breakout rooms.
09:03:18 If you do from a breakout room please first thing set up a leader, someone who will take notes and do that reporting at the end.
09:03:24 Finally, just to create a focus on the discussion we're not going to solve the world's problems in two hours.
09:03:31 But what we are trying to accomplish in the next two hours is identify what are the outstanding problems, what's needed to make progress, and for those of us participating in this working group, how can our skills being combined to help address these
09:03:45 issues.
09:03:47 So with that, I'm going to stop sharing my screen and I'm going to pass the shoe over to Peter and john to lead the following discussion, go ahead.
09:03:58 Okay thanks Bruce, I guess, john and i sort of nominally agreed that we sort of share the responsibility for leading this along.
09:04:09 And I think I said we have several people lined up who are going to give some short talks, but I would I would take the sort of the the chairs prerogative and kick off.
09:04:22 So those of you that have been looking at the, the Slack channel will see that I attempted to sort of kick things off by trying to stimulate various people including myself, putting down some possible responses to Bruce's challenges.
09:04:42 And so what I'm going to do is essentially briefly.
09:04:46 Begin by speaking to at least my list just to sort of get things get things kicked off at least if I can find my.
09:04:56 So I'm going to share my screen here.
09:05:01 So,
09:05:04 just to kick things off, so we are interested in in zonal Jetson PD scare staircases on on john planets.
09:05:13 And, of course, the one thing to establish of course is what is already known and established.
09:05:19 And I guess this is a kind of shameless plug for the book that Boris Galpin or Galperin and I helped to edit with a number of well quite a quite a lot of authors several of whom are, are also part of this KITP group, for which you can see, as an example,
09:05:45 the minister was just sort of summary of the situation in around about 2019. And there's no shortage of various models and ideas, where these jets come from and how they appear and what governs, to some extent, some of the properties.
09:05:58 But there's plenty of that is is still pretty open in terms of how long tests these these ideas.
09:06:05 So in terms of this session.
09:06:09 I think what we're going to try to do is, is to encourage people to think in terms of what are the, the pressing high priority outstanding problems and questions.
09:06:18 And what is actually needed to make progress.
09:06:21 So it was one
09:06:25 one possible way forward. His here's, here's my sort of immediate list. So, there are various things that we do know but there are various things that we don't and one of the things that we don't know about Jupiter and Saturn and Uranus and Neptune jets
09:06:38 are how they energized.
09:06:41 So, there's all sorts of processes that are engaged in in energizing motion.
09:06:49 driving turbulence in these, these atmospheres.
09:06:53 We know that it's very likely there's deep convection going on due to the interior heat sources. There's boys convection associated with the condensation of water and other constituents.
09:07:07 And then there's various forms of instabilities Barrett tropic Barrett Clinique instabilities that may be relevant.
09:07:14 And these will have various implications for the, for the structure of the flow but exactly which is most important in terms of driving the jets that we see is still I would suggest somewhat somewhat uncertain, and there are various questions there that
09:07:29 needs to be thought about.
09:07:32 Okay, so that's where they're highly energized, how they dissipated. So we, we often put dissipation terms in our, in our models we use sort of linear drag or viscosity or various, various sort of things, various devices in models but how how these jets
09:07:51 really dissipated.
09:07:53 And this I think is still somewhat tricky question, and of course will bear quite considerably on how we formulate, how we formulate our models, I mean, are the Jets primarily dissipated at large scales or on small scales or whatever is, is it due to
09:08:11 meet dissipation and the MHD effects of depths or is it radiative damping or gravity way breaking or whatever. And this is something that I think still needs to be to be addressed and thought about all emergent jet structures the result of some sort of
09:08:28 self organized criticality pulling the, the flow towards an equally abrasion, that is effectively a state of marginal instability.
09:08:39 So, I think Tim Dowling is going to talk to us a little bit about this in terms of the Arnold second stability theorem. So something that I that I also mentioned in my talk, couple of weeks ago.
09:08:51 And the question then is, you know, is this a useful concept. If so, how do we use it.
09:08:56 If not, then what else should we be using in terms of mechanisms or criteria.
09:09:04 Hello Steven with the Jets.
09:09:06 They've been observed on Jupiter, for example, their observations going back at least a century or so.
09:09:14 That seemed to indicate that the Jets don't actually change very much.
09:09:18 But we saw for example in Laura copes talk that there are sort of situations when these jets can migrate around. Several studies have indicated this.
09:09:29 And then there are various other events that seem to take place that have the ability to disrupt the sort of jet behavior, what was the big example for example in 2011 on Saturn when there's a big episodic disruption seems to happen on seasonal timescales
09:09:45 as an image there that you can see
09:09:49 within the jet structures course we see all sorts of large scale, Eddie like features Eddie's and waves, and so on. And what's the relationship between them.
09:09:59 I mean are they are they actually driving the Jets or are they actually feeding off the jets in some way and if so, if so how and what implications does does that have for the 3d structure, the chemical origin, things like the Great Red Spot, which you
09:10:14 can see here and you can see my point of moving around as if the famous North polar hexagons on Saturn which is a rather remarkable feature. Most recently with Juno mission we've been seeing these clusters of regular arrays of cyclones around the poles.
09:10:29 And do they have any relationship to two jets or latent jets jets that are not as obvious as the as the ones that lower latitudes on, I guess john planets.
09:10:45 And finally, that there's a question that I think interesting with the present company is what can we learn about these gas giant jets from possible analogies with the terrestrial oceans and it's been known for quite a while now that on sort of just a
09:11:01 bit larger than visa scales, there is, there are features in the oceans, particularly the Pacific, that are certainly revealed in in high resolution models that are remarkably reminiscent of some of the jetlag structures that we see on the gas giants
09:11:17 although much more latent and more difficult to see without, without a certain amount of of averaging.
09:11:24 But are there insights there that we can learn, either from the oceans about the gas giants or learn from the gas giants about the oceans and I think, you know, there are plenty of things to be thought about there.
09:11:35 So there's plenty of outstanding problems.
09:11:37 What do we need to make progress, and we usually say, Well, of course we want more observations.
09:11:45 And in particular, I guess I'd highlight that we will refine determinations of the deep structure.
09:11:51 Below the clouds that we can observe which typically means ingenious ways of remote sensing through gravity of magnetic fields, and maybe even seismology techniques have been proposed.
09:12:04 And we like to be able to look at PV structures that much higher spatial resolution.
09:12:10 So, I've played around with this.
09:12:13 In connection with Cassini data for some 20 years now, and the best we can do is something like a two or three degree horizontal resolution and latitude and longitude, which really isn't hugely,
09:12:29 hugely, hugely affected we would like to be able to resolve PV structures on a significantly smaller scale much as we see in the clouds patterns that we can see here really looking at around the red spot for example.
09:12:43 The other thing is, we really need observations on much longer time scales and we've had so far and more detailed time scale so we probably need some sort of monitoring observational monitoring program that really really looks at this properly.
09:12:59 And then what about models.
09:13:01 So, I mean, I think I would argue that we need more quantitatively realistic predictions it's all very well having idealize models that can give you sort of ballpark, sort of predictions that you may or may not be able to compare and testing observations,
09:13:19 but to really test models you really need to refine these models so that they become more quantitatively realistic. And this means refining the, the kind of models that we have been building so far either the sort of weather layer type models which sort
09:13:34 of idealize what happens in the deep interior, or the deep models that idealize what happens in the weather layer.
09:13:41 And maybe what we should be thinking about is moving towards some sort of hybrid coupled model which couples whether there's proper weather layers to properly deep conviction, models, eventually in order to be able to do proper quantitative predictions.
09:13:58 So that's my pitch. And I'm going to sort of stop at that point. And so we can sort of open for discussion for people might want to disagree with me or elaborate on what I've what I've proposed.
09:14:14 So I'll stop sharing there, and open the floor for some comments and discussions.
09:14:25 So, please raise your hand if you would like to contribute something
09:14:36 crystal clear, everybody agrees with me. Well, I mean, I think, I think it's that you've laid out the big picture.
09:14:43 So, in some sense, I would argue, excellent overview of the big big picture, open questions are there other big picture open questions that people are would like to bring forward already.
09:14:59 And, or should we go into more detailed arguments.
09:15:03 and then let let people go from there.
09:15:13 I'm gonna, I'm going to climb the ladder.
09:15:18 Okay so Peter I don't know if we came up with. I remember they were people giving smaller presentations, but I don't remember if there was any order.
09:15:40 Ah, no we didn't actually agreed that they had before. Let's just flip a coin coin. So,
09:15:39 can you choose.
09:15:41 I'm, uh, let's let's actually go back and forth between kind of different arguments, and I see Phil Marcus happily I'm up near the top of my screen, and therefore I'm proud to introduce Phil.
09:15:56 Take it. Thank you. Yeah. Let's see. Can I share my screen I guess I hope so too.
09:16:05 Alright, so let's see if this all works.
09:16:11 Okay, so.
09:16:15 Okay so here. Here are my comments, and I'm going to try and make them. Addressing so they play into it, Peter said, I think that the concept of PB staircases is way too general a problem with unless you really tie it to the data, and that includes both
09:16:34 observations.
09:16:36 And I think experiments that that john, and, and, and Peter can do and others, and and the reason I say that is because I just don't think there's going to be a one size fits all solution to these problems me, even on Jupiter itself, the northern hemisphere
09:16:53 looks extremely different than the southern hemisphere. So, is it different physics, or is it the luck of the draw or is it initial conditions. And certainly, if you look at that the zone belt system on Jupiter.
09:17:09 It's actually quite different than it is when Saturn, or on Neptune, or Uranus, or in a capillary and disk where you make zones and belt so I really think that progress can be best made by, by, by by really trying to decide what specific phenomena that
09:17:29 you're trying to get, and then try and make it universal.
09:17:33 trying to get, and then try and make it universal. So the other thing is I want to emphasize, and I spoke a little bit about this a couple weeks ago is that right. Today's not 3d, and and and the physics of 2d turbulence and zonal ization is really quite
09:17:48 different in two dimensional, and three dimensional calculations and theory, but it's also really different. In the observations. So, um, I presented last time to figure on the, the right here, which is basically the equatorial sono philosophy on the
09:18:10 the meters per second, as it is per second, as a function of height so here we are down around here with a one kind of bar level. And, and there's quite a bit of variation, what goes in the east direction goes to the west direction goes back to the east
09:18:26 issue. I should go up an altitude and. And here is a similar slide on the left that was prepared by at sang.
09:18:36 It's around the red spots so the latitude, this picture goes between about 32 and 14 degrees south. And in the vertical direction is the vertical it's the log of the pressure in units of a bar.
09:18:53 I'm sorry Phil I think you advanced your slide but that's not showing up on our screens. I'm sorry, what's not showing up the we're still seeing the first slide that I'm sorry, I'm still in the first line I'm looking at our picture on the left here that
09:19:04 panels right panel.
09:19:06 So,
09:19:10 so yeah. The.
09:19:14 Yeah, hold on a second here.
09:19:25 I'm
09:19:25 trying to figure out advance my slides, when I'm in this mode. Let me
09:19:35 for a second.
09:19:38 a second. So, yeah.
09:19:42 So, I'm on this side on the, on the left by putting this little bit but I'm looking at that the east west velocity. So, so our interest rate is coming out and blue she's going in or what are just read this in the east direction bluish is in the, in the
09:19:57 West direction.
09:20:00 And the colors are the extreme colors, plus and minus 50 meters per second. And what we see is that these these jets really do even if the latitude of the red spot changed significantly.
09:20:14 So, if I, if I, you know, I'm trying to represent a calculation, as as as reality, and I'm saying wow look great at nine tenths of a bar, and I've really established that my captain america calculation.
09:20:32 Looks like the observed, east, west winds of Jupiter which are about where that red bar is on the left panel, and then you know what what happens if I go up or down in the atmosphere a little bit but the zone or flows, don't look anything like that they
09:20:46 may be very constant over time that over three decades we always see Easter jets and westward jets at the cloud layer, about a bar at the same latitude know locations if you go up or down in the atmosphere.
09:21:01 it changes like crazy so somebody presents a numerical calculation said look, I've exactly reproduced, what's been seen in the cloud top observations.
09:21:11 I said yeah but but what in your calculation, said it right where the coincidences that were the cloud top observations are so I think we have to be really, really careful about making comparisons with Jovian data that the Jovian data on the left we got
09:21:40 East West variations by looking at the thermal wind equation. We got the thermal wind equation results by using observation Lee measured temperatures on Jupiter.
09:21:40 There may be very little variation in the east west flows that we see at the cloud top level, but there's certainly a strong to Kato variation in the temperatures which would change the, then the thermal window over a decade old time so it's a bit of
09:22:16 paradox to me of why we don't see it the cloud top levels of variations in the zone of velocity, but the thing that causes them to change vertically the temperature does have that variation.
09:22:15 So, again, I'm quite sure why.
09:22:20 Okay. Okay. Thank you, Phil. We were like five minutes, buddy.
09:22:29 Quick slides, real quick, real quick. Okay, let me go really fast. So here's my concern minute by minute.
09:22:37 Okay speech genre not one minute. One minute. Yeah, I'm gonna, I'm gonna go, right. So, the,
09:22:48 the atmosphere right. This is subject to a lot of debate below about 15 or 20 birds probably very convective I'm highly turbulent between 15 and 20 bar, and maybe one bar, it's, it's stable in the sense that you can define a Rossby defamation radius and
09:23:06 abroad Vizsla frequency, but it's intermittently come back right we see we see lightning going on there, above the water classify bar above maybe one bar.
09:23:15 It's very stable a stratified, so perhaps the zones are probably deep and there's a lot of inertia because the density increases as you go down. So the governing physics is probably in the convective layer, but most of the observations that we see are
09:23:28 in the stable layer, and that's a bit of a conflict there. So, want to know how staircases occurs in a region where the upper region is very stable and the lower region is fully connected and I don't think that we're going to get the full answers through
09:23:43 boost and ask approximations, because we're talking about going over many, many pressures scale heights.
09:23:50 And this brings us into the question of if I think that the Buddhists are very significant and telling us about what the zone of flow looks like they're very very sensitive to that.
09:24:01 So, the questions I think that we should be looking at is how deep do these vertices go.
09:24:07 What do I do if I got a great flow that produces zonal flows but no vortices or vertices with the wrong sign as many simulations have done, or they're ephemeral and they're not long lasting, or they look Gaussian and not hollow like the actual board to
09:24:22 seize on how much I trust the interpretation of June and measurements which are now kind of flooding the literature.
09:24:28 There's a lot of questions about how you go between a brightness temperature and the thermal kinetic temperature on the night change everything. And finally, I want to say that data is really important and, and one of the things we don't have as Peter
09:24:41 mentioned, is, is, is, is good spatial resolution necessarily and and data over time so several years ago we came up with a method which I call automatically affected correlation image of symmetry, where you can use piv and Civ methods of the lab to actually
09:25:01 apply it to, to Jupiter. This was done several years ago before I got involved in convolution neural networks, and I can tell you that there are much better AI ways of doing it now.
09:25:14 And I really think that if we, you know, pull our resources together one thing that we could do is we could make these methods of doing cloud tracing to extract the winds Jupyter, not just from satellites, but from ground based things telescopes, and
09:25:30 that would really increase our knowledge of what the flows look like so I'll stop there Chris my five minutes is low income and going. Thank you.
09:25:46 Okay.
09:25:47 Thank you, Phil again Do we want.
09:25:50 Any questions immediately.
09:25:57 Anyone.
09:25:57 Okay, I Can I ask a question, I, I cannot find the hand I only can find a hamster to upload so I'm uploading but now, how do I push ahead now asked the question.
09:26:13 Only the elephant make a common to what Peter was saying in the beginning.
09:26:19 First of all, I I really was feel about difference between 2d and 3d flows.
09:26:27 We did experiments in in universities still wrong is that they think turntable.
09:26:31 But effect, and we looked on variation of potential participants.
09:26:36 I was hoping to find the movie but I couldn't find it. That was quite a few years ago and was uploaded to the town variation of the potential of this the profile, and it was anything, it was really time dependent from motivation time and not TV space
09:26:51 and spontaneous profile which you could measure.
09:26:54 And so I bought a tree. And you could see whatever you want.
09:26:58 Not staircase at all it was Celtic on all scales, and you should you ever need it.
09:27:22 analogy between Rosebery waves and internal waves and vertical structure and the ocean for example unstable is tied to a flood and potential with this variation and horizontal.
09:27:35 And we did it under Obama trends and found the scale which was analogy to the self serve scale. And from this from sort of scale you can you can infer right dissipation.
09:27:48 Direct escape from this is from this potential little disappear. You could actually extract the rate of inverse cascade and
09:27:56 we, we use the same idea, the spirit of we have a recent paper and Dr. Jeff physical of social others, in which using this monetization of potential artistic profile liquid extract the right of inverse damage escape.
09:28:11 So,
09:28:14 so I was asking for questions for Phil.
09:28:18 So this was a general comment I think we can come to this after we finish these talks for for feel.
09:28:27 It also goes to feel empty Peter quick because again, we're gonna with this money talks, we have to attempt to stay slightly on schedule. Or else, forever.
09:28:46 What I'm trying to say is that I don't even know what fill up show instantaneous profile or time every horizontal average, because they will all get different results.
09:28:49 I think that's that's I think a key question that we have to, when we're talking about PV staircases we have to get to that General.
09:28:57 And also it will give you different answers if you consider different kids. Right. You may, you may see a lot of skills and contributor to see variation, you may need to wait for many years they just cannot do it.
09:29:11 It's time for him to first never 10 second, come 10 second.
09:29:18 Yes. When Jupiter, a single. The longitudes look all the same in terms of the zonal flow almost identically.
09:29:25 When you do the cloud tracing analysis. On the other hand, on Neptune. If you don't average over time and longitude, you probably won't realize that zonal flows there, so it's completely different between the two planets.
09:29:38 And maybe Tim Gallagher comment on that.
09:29:43 I don't think we can see much on Neptune.
09:29:46 Were unless she's down to average over time, and longitude right i mean it doesn't look reasonable.
09:29:53 It's a mess yeah if you look at like Larry's from ops keys and Heidi Hamels stuff over the years that there's quite a huge scatter actually in the zonal cloud tracking from Neptune and Uranus both.
09:30:05 You don't need to go too far away as Nick mentioned Logan out on oceans, you will not see the Jets until your average, the signals only, then it will see system objects, even in those oceans.
09:30:18 Okay, so actually I still want to move forward. I, please if you do have questions I'm not attempting to truncate them, I want to move forward with these so we get through everyone's contribution, and then I think let's write down some of our questions
09:30:32 let's keep like one question after each talk. And then let's go at it, when, after we when we have this group discussion that Bruce mentioned at the end.
09:30:43 So on that note, I'm gonna know it does to the people put questions in the chat, so be great.
09:30:49 That'd be ideal.
09:30:50 And then we can return to them. If we don't do not get to them. Presently, ok so now at the top next person top of my screen is Chris Jones. So Chris How about you go.
09:31:04 And you're muted.
09:31:16 I'm unmuted now okay you can hear me okay, and I'll get off my thing and you can share the screen. Yeah.
09:31:15 So share screen. Yeah.
09:31:17 Okay, not shared yet.
09:31:27 Sorry.
09:31:34 Okay, you can see that can you. Yep. Yep. Okay, let's see if I can move on then.
09:31:46 Yeah, okay, that'll probably do I think that he needs to be full screen. Um, I just want to make some points about the importance of the bottom boundary condition in all these problems about jets Jupiters jets and so on.
09:31:57 Um, first of all, I mean we know from lots of previous work that non magnetic deep convection models can get nice multiple jets sort of look vaguely Jupyter like, but only if you've got a stress free bottom boundary condition.
09:32:14 And the Dynamo models give zonal flow in the equatorial regions, but they don't usually give the high latitude jets. And the reason for that is again the couplings of the Dynamo region is too strong for the high latitude jets to survive.
09:32:28 So again, it's bottom boundary which is completely dominating. What you see right throughout the whole whole shebang now possible to escape routes out of that is some recent work by guesting and Victor about possible Staveley stratified layer, I think
09:32:46 I saw that man is Victor is actually.
09:32:50 Yeah, so you may be able to add some comments or stuff. But that's one way out but it also brings a whole lot of other problems which we'll talk about in a minute.
09:33:01 And the final thing I want to say is we really need to understand how magnetic rating of the zone or jets works.
09:33:08 I probably, I and our awful lot of other people here have always thought, the problem is simple in the sense that you just go down deep into the atmosphere where the magnetic field starts to operate and its own or jets get stopped, and that defines the
09:33:24 bottom boundary of the, of the whole thing.
09:33:28 And that's
09:33:32 something we've seen.
09:33:35 But, I think, actually, the problem is more complicated than that.
09:33:39 And if you look up the equation about what determines how magnetic field actually stops zone all jets. It's basically the magnetic wind equation, which is the five components of a co of the voltage it says exactly analogous to the thermal in the equation,
09:33:57 so it's got a du five IDs so it tells you how the you fi. The zonal flow changes with depth.
09:34:05 And for thing that does it if it's a magnetic field is this be not DJ five IDs so j phi is the current in the fire direction.
09:34:14 And you can ask yourself well to make any sense of this we've got our estimate what Jay fires.
09:34:20 Really, that's pretty simple owns law tells you that j phi is something like sigma.
09:34:26 You cross be so the order of magnitude of it is be if that's the vertical field, and um is the meridian all feel Mariano flow.
09:34:36 Okay, and that gives you some estimate of that. And then you can see whether you can actually actually break the seven flow.
09:34:44 When we don't know what the meridian or flow is down deep down inside Jupyter, it may be small, most of the models that usually is fairly small, it could be same sort of sizes the zonal flow possibly certainly Kong as our models, so that you can talk
09:35:03 to about.
09:35:06 Certainly, how to merge the animal flow which is comparable to that only anybody really thinks that the meridian flow can be substantially bigger than the as the music flow.
09:35:14 So that really means that this term is really limited in what it can do.
09:35:20 And the key parameter that turns up is the assassin number it's really the local level Sasa number.
09:35:28 And that's the list. I mentioned was combination sigma squared over to omega.
09:35:34 And that is really what has to be order one in order to actually get a significant amount of du far by the Zed. So if the assassin numbers order one you could reduce the zone or slow strength bar factory and 300 kilometers and that's fine that's all,
09:35:51 be all consistent with everything we know about Jupiter problem is that 3000 kilometers depth, which is where the Juno data suggests that the Jets go down to a value of lambda is nothing like large enough, it's only about three times 10 to the minus four,
09:36:11 which is just far too small to give any significant magnetic breaking the electrical conductivity increases rapidly with that so lambda gets up to one 7000 kilometers below the surface and that's where the Dynamo operation.
09:36:29 But I doubt if the gravity data is really consistent with tonal flows as deep as that.
09:36:37 The IRJN coefficients will be a lot larger is actually insert.
09:36:42 So I mean if you look at this picture of the electrical conductivity, you can see what the problem is.
09:36:47 3000 kilometers we're down here, and you know log scale that's something like between one and 10 is the electrical conductivity and Siemens Mater. What you need it to be as 10 to the five seasons for me to which is what it is up here, down where you actually
09:37:04 hit the Dynamo region. 7000 kilometers besides below the surface.
09:37:10 So the transition zone as well yeah so this.
09:37:14 Yeah, so the problem here is the electrical conductivity is is nothing like low enough high enough actually to actually block the thing at 3000 kilometers.
09:37:25 So, that's the main point I wanted to make. I'll just show you a picture of one possible way around this which is being proposed by Tom a dusty and your hand is Victor recently.
09:37:39 And this is a picture of the zonal flow in their model. And what they've got here is a Staveley stratified layer, which lies between dashed lines there so that Staveley stratified layer.
09:37:54 And you can see that that really does do the trick. But he's vertical flows these these zonal flows, which are remarkably GS traffic in the deep interior and their model and we expect that because it's pretty near a diabetic down there.
09:38:09 They do terminate when it starts to hit the stage a stratified layer. So that is a way of getting around the problem for the terminating the Jets.
09:38:22 The only problem is that as I said here. even week zone will flows in this stable region actually tend to wipe out the non access symmetric components, done that very effectively and Saturn, of course, and there aren't any non access symmetric components
09:38:36 of the field and Saturn, but in Jupiter, unfortunately, we can still see the non access symmetric components. So this model actually produces a field which is to access symmetric.
09:38:47 So I think that's about it.
09:38:49 So I uncheck you and share me here.
09:39:02 See if God share yourself. Yeah, okay, I'm Shannon myself Yeah, Okay. So, so that's the problem that we have so really the nice idea that we have that, it was all going to be solved when we found the magnetic field vamping down those that jets going down
09:39:15 that will produce a nice termination. And we'd have a nice little model I think Tim Dowling mentioned this sort of model that see the bottom boundary was a spherical cap wherever electrical conductivity comes significant, and then up above and you've
09:39:31 got the jet region there. And then that would all be consistent but unfortunately, we do have a serious problem because the magnetic fields that we see.
09:39:43 I just not strong enough to actually do the job at the 3000 kilometer level.
09:39:49 Okay, I think I see one. Thank you, Chris. I see one question I think from your harness is that right or is that is that a hand or is that a class. It's a hand it's bringing more comment because Kris was presenting our papers so.
09:40:02 So just, just a brief comment on it Thank you Chris for presenting it and and as you introduce nicely we have a real problem preventing them from going deep actually.
09:40:13 And if they go deep actually we could have an overheating problem possibly on energetic problem that say so. So there was so much dissipation by magnetic forces actually that we would need very strong rain on stresses or whatever to drive to win so there
09:40:27 will be an unusually problem as well. So you have to prevent that from going deeper 20,000 kilometer is a reasonable volume but the probability is help you stop him there.
09:40:35 It's not understood and, and we came up with a state layer idea this was a shoot with the Christians and so there's another paper, we published.
09:40:43 I think last year with all the Christians and it was a Cartesian box simulation where we first tested this idea. And now with tomorrow we have the 3d simulation.
09:40:52 And the idea, basically, is that you still have a thermal winter equation. That explains the du fight is that, but no you actually produce the variations and entropy by basically tapping with very weak Mariano circulations into a stratified layer and
09:41:14 ju have a strong gradient and entropy and that does the trick.
09:41:19 Yeah. So so so Your Highness, maybe you'll be talking about that when you present.
09:41:22 I don't present. Should I present you didn't tell me I should present you yeah you were you were on the outlets.
09:41:29 That was the idea of those. Okay, that's fine for me, but it presented. I could show a bit more but I don't have anything prepared.
09:41:37 Okay, okay.
09:41:39 All right.
09:41:41 Okay, so I'm going to hop back, top of my box right now as Tim, Tim. Go ahead.
09:41:59 Okay, so I just had to slip in this we're talking about raspy waves and this is a current snapshot here I'm in Kentucky Louisville, Kentucky and we have a beautiful meander that's very unusual no one remembers it coming down quite so strongly through
09:42:12 Texas so we're getting about 40 or 50 centimeters of snow in the next week from Texas, which is fun because it's a big meandering raspy way.
09:42:22 All right, I want to just briefly talk about the different conflicting geometries and a lot of factual points, I'm going to make have already been made and, and even my points have already been modified slightly.
09:42:32 But we have two main domains that have very different geometries we have the troposphere, and the interior whole start with the interior. It's very cylindrical as you just saw from the rapid rotation, and from the gyroscope but Taylor problem and effect.
09:42:46 And so it's like a two, but about the shortest tube you can imagine because before it becomes a to have it's kept by these hemisphere so the troposphere what Peter Reid was calling the weather layer is at one end and that that wouldn't least we can see.
09:42:59 And then what I'm calling the conducting layer and I've been corrected already to just call it the bottom of the two we don't really know what's breaking the winds there but I'm closing it as a question, not as a statement so what is what is the bottom
09:43:11 boundary there, but we do have a tube. And so the theme that's going to come across for Jupyter both in these the interior domain and the troposphere domain is this idea of boundary control of stretching for TriCity.
09:43:24 And what I'm going to argue is that the interior is very foreign, and it's geometry to the troposphere when we get to the troposphere so the first. People were any Ingersoll de pollo back in 1982 looked at this problem for a booster interior interior
09:43:47 didn't have any sort of steady core they didn't have a core it just went all the way through like a sphere inside of a cylinder. And they got minus three beta it's negative because the stretching Portuguese in the denominator of the potential for charity
09:44:01 And so it's quite reasonable, I think, to develop a PV staircase and by staircase I take it that you mean that you're trying to avoid critical latitudes where the PV gradient changes sign so a PV staircase with strongly alternating jets and we certainly
09:44:15 have empirical evidence, going back to the garage and vortex the analysis I did with Andy Ingersoll back in the late 80s, we actually detected the deep jets on Jupiter.
09:44:25 And now and then the GALILEO probes ID, strong gets and then that but you know it's informing them.
09:44:31 No one's mentioned this, but a really nice rule of thumb for the Juno results and the Cassini results are that the Jets on Jupiter and Saturn appear to be about as deep as they are wide.
09:44:43 They're a little deeper on Saturn but the Jets are a little wider and that's a nice rule of thumb and may actually be a strong clue if we can figure out what it means.
09:44:48 Okay, let me go now to the troposphere where we have a spherical shell, but we have a spherical show with extremely strong dynamic topography from these interior jets and the price of this interior foreign PV staircase I showed john or know this a couple
09:45:03 days ago and he said it sounded like a invading hordes of beta coming in and that's kind of what I mean, you have this interior foreign PV staircase is, it may not be three beta but it's it's four and it's different.
09:45:15 It may be quite strong. And it's producing multiple critical latitudes. So I don't know if critical attitudes are taboo in this workshop or not but I would argue that we have a lot of empirical data from late 80s through the 90s to the 2002, the 2010 2020,
09:45:30 we have a half a century of data showing that in fact Jupyter actually does have critical attitudes. In fact, I would argue every time the zone when changes sign there's a critical attitude and Saturn as well.
09:45:40 And so the question is how does that work and so I have what it called Jupiter style get stability which is this boundary control of stretching for tissue you see it in the interior, but you also see it in the troposphere, and the critical ladders latitudes
09:45:53 are being stabilized by becoming supersonic in quote so when I'm in quotes with my mock numbers, I'm talking about raspy waves not sound waves so I'm just going to dispense with that and just call things mock numbers and supersonic.
09:46:06 Alright, so how do you stabilize a critical attitude. Well we get very strong guidance from the Kelvin, Arnold sure stability criteria, the first and second Arnold's the stability criteria, but those have traditionally since 1880 when really first came
09:46:20 out with this inflection point.
09:46:34 Every single one really cool tourney Stern, which are just different terms being added to the full potential or Jesse gradient short tough which is logically equivalent Ripa which extends to the premiere of the questions all of these are done in dimensional
09:46:43 form. And so my modest contribution is to non dimensional eyes those when you do that, the non dimensional number it turns out to be the analog of the Mach number for us P waves, so I'll say Mark number in quotes and the upper line here is the Mach number,
09:46:56 number line, and you find the two stability criteria honors first ability criterion which includes really cool, turning certain for tough report all the special cases or as a logical equivalent turns out to map to the negative half of the month number
09:47:10 line, which I don't know, maybe offline and we don't have beers here because we're all at home but we could talk about whether that's a institution wide embarrassment or not but the entire 20th century basically was devoted to the negative Mark number
09:47:24 line. The second stability criterion which is less well known Arnold seconds left turns into a statement of supersonic, and so actually both branches are supersonic the negative branch, the first the first stability theorem is what I would call paranoid
09:47:41 supersonic its supersonic in the sense that the waves are traveling downstream. So why do we even have a negative branch. Well, unlike sound waves and gravity waves which are Mach number in fruit number, you have waves that are uni directional so they're
09:47:55 only moving in one direction at a time. And so you don't have the luxury of having upstream waves sometimes, sometimes the waves are only going downstream, that's the negative number branch.
09:48:04 And so the waves are already fleeing away from you so you don't have to do anything with the current to get them to go away.
09:48:09 And then of course supersonic is when is when the current or the wind is blowing fast enough to push the waves downstream that are trying to come up through.
09:48:16 So these two actually concatenate very nicely. If you do the reciprocal mock number, and they slept together and you get a stable is just a very compact statement.
09:48:26 And notice that, for example, homogeneous pv modularized Pv is zero. So, that's another long discussion that's been going on for for several decades and never, never non dimensional eyes, and so this non dimensional eyes is the concept of of PV commoditization
09:48:42 that says zero on the reciprocal lock number line, and one is more like a sonic TV or a marginal stability, or you could call it choke PV. So anyways, the whole, the whole bit of that we can do with these stability theorems he's on stability terms we
09:48:58 can, we can bring them down to a single five word statement which is an inbox here, and this I would, I would put this as a one size fits all resolved.
09:49:15 so here's my questions. First and Jupiter's interior what is the shape of, okay, it's not a conductive end of the two perhaps what is the shape of the end of the to the inside part of the tube in the interior.
09:49:25 Another word what is the effect of beta what is the environmental PV gradient.
09:49:28 The one that Ingersoll and color got minus three beta for number two what do the rotation and the density or the cylindrical and the spherical geometry, how do they use those to geometries interfere with each other.
09:49:40 And this means you can't use a business model for the interior and I think some of the models we just saw, or not they're just really exciting to see these, these non moves into your models, but again to peer reach point you really have to get to have
09:49:52 the atmosphere of the troposphere and the interior in the same model.
09:49:57 Third experiments of the non was Netscape numerical models, and also plasma tubes, you can have them, the mat uniform magnetic field in a laboratory plasma tube.
09:50:06 There's a lot of literature on that.
09:50:09 But you could do it with hemispherical ends we could do it with radio the undulating typography on the tubes.
09:50:15 There have been two papers that I'm aware of that discuss stretching words state in the plasma tube experiments, but very little has been done actually playing with the geometry of the ants and so that would be a lot of fun and I think you know, they
09:50:26 get their results in microseconds rather than in hours and days interpreters troposphere of the first question I have is how do the multiple critical attitudes that we see, there are like two dozen critical attitudes entrepreneur, how do they negotiate
09:50:39 to stay mutually supersonic if you only have one critical attitude you can get into its reference frame. And if you have more than one that you can't do that trick twice, you can't do separate galleon transformations for two or more we have a two dozen
09:50:51 on Jupiter, question number two, how does the Information link the first pair of clinic information like in a troposphere does it, is it possible that troposphere is so flexible, that it could adjust its LD as part of its plan to avoid sub Sonic critical
09:51:05 attitudes and experiments rotating tanks have been done quite a lot actually. We have experts on that in the on the panel here but what about radio Lee undulating topography to mimic that strong dynamic topography that Jupiter has.
09:51:20 I know one study that's about to be submitted for publication, but I think there's room for quite a bit more. And finally, this idea of Jupiter style sure stability which is this boundary control of stretching where to see we see this in the interior.
09:51:31 And we see this in the troposphere, where else might we see it. Where else for example, do we have a fluid system that has the discomfort of having to live next to someone else's PV staircase.
09:51:43 Ocean circulations over strong bottom topography perhaps plasma analogies in nature rather as well as in the lab. And what about planet formation like Phil Marcus mentioned proto disk analogies, and then my last thought is, I would ask everyone who is
09:51:57 looking at numerical models and data to please plot the reciprocal of the analog of the Mach number, and.
09:52:06 And I promise you good things will happen and scales will fall from your eyes, etc. That's it.
09:52:18 Okay.
09:52:19 Thank you very much. Do we have one quick question.
09:52:26 Do I see Your Highness, I see your hand up again for Tim.
09:52:33 I think that was still from up from last session, I understand. Thank you very much. Okay. Any, any one, one quick question for Tim anybody. If not, we will keep going we're actually approaching the hour.
09:52:49 Okay, Great.
09:52:49 Thank you, Tim.
09:52:52 I think the last speaker, I'm gonna. I should be emailing Peter to check on that but I think our last speaker in that case would be Daphne
09:53:02 did, yes. Thank you. Can you hear me well.
09:53:05 I can share away Daphne.
09:53:16 Good.
09:53:17 It is.
09:53:21 Okay.
09:53:21 So Good morning or good evening. Good evening everybody. So my name is definitely messed up. I'm a PhD student working at fe laboratory, NASA in France, under the supervision of IV and Megan bars.
09:53:37 And what I wanted to briefly presenter today is some experimental insights on the on the topic we're discussing today. So the experimental project that I'm going to present was initiated by john in 2015 when he came when he gave me nothing.
09:53:55 And so he built with a small cabana first preliminary version of this experiment in NASA and that's the, the continuing of these of this project.
09:54:07 So basically, the idea was to build a laboratory analog of deep seated objects. And so the idea is that you need to have an experimental setup where the friction the number is as small as possible.
09:54:20 And so what you need to do is to work with large containers which eating very fast. So what we do is that we use a setup. We use a cylindrical tank which is one meter in diameter and 1.6 meter height, which is filled with a deep layer of water, and we
09:54:39 rotate that 75 rotations per minute.
09:54:42 rotates at 75 rotations per minute. So that's the the tank and then because of this fast rotation the fleet free to face is a parable. And so we are provided with a stronger strong topographic BJ affecting the setup, or into the to the rotation.
09:54:57 And then as an analog of the the small scale conviction in the deep interior, we are going to circulate water through but unpaid, which is placed at the bottom of the tank, and the circulation occurs on the following pattern.
09:55:11 So it's a polar polar pattern with 128 inputs and outputs.
09:55:18 So you have here on the right, two pitchers of the experiment at first, rotating with the freezer face that you can see here, and the bottom right, you have a picture of the button plate for each The first thing is performed.
09:55:34 So you can see that it has slightly curved shape, simply because we wanted the beat effect to be uniform across across the domain in our experiment.
09:55:46 Okay, so in terms of non dimensional parameters, with the setup we are able to reach it my numbers down to about 310 to the minus seven. So we have the radius friction that we wanted.
09:55:58 And if we base the Reynolds and Rosebery number on the local forcing scale, l, we find that the Reynolds number of the flow is typically of thousand, and the local resume numbers typically have 10 to the minus.
09:56:10 So we are dealing with the turbulent flow bit which is still largely dominated by irritation largely was a dress.
09:56:17 So we have a strong topographic BJ effect as I said a small scale for seeing as small as possible. and we are both to reach quite large cluster index, because for instance in a typical experiments The, the right scale is about three times the transitional
09:56:35 scale so we should be in the circles on a strategic regime which is relevant for gas giants.
09:56:41 So I didn't have the time to detail any results I just wanted to briefly illustrate here, the kind of results that we have obtained so far. And here you have for example the fact that we have identified two different regimes objects, depending on the
09:56:55 first thing amplitude.
09:56:57 And we have shown that the the transition from the first to the second regime of some objects is due to a resonance of the rescue ways because of the affection of this waves by the by the underlying, some of them.
09:57:10 So if you want to test we've just published a GIMP.
09:57:16 So I've listed here the advantages and limitations of search experimental approaches for single photos.
09:57:23 So basically the main advantage is that we are dealing with a fully three dimensional system.
09:57:29 So in that, in our case the fact that the system is fully 3d are those to support a bit more the deep hypothesis, the deeper scenario for the Jets.
09:57:40 Second important point is that using particle image below symmetry what we can do is have very long time records of high resolution Felicity fields, and this we can study very precisely the interaction between the trouble and flow and the, which is fastly
09:57:55 evolving and the landscape objects which are slowly moving on the contrary.
09:58:02 So for instance, if you were to do the same.
09:58:05 The same study with the 3g DNS. If you were to simulate 30 minutes of the experiments you would need 13 days of simulations on using 2000 CPUs, so that it's, it's really closely and experiments we we can just let the experiment run for hours and it's
09:58:25 it is. So despite all those advantages, there are some limitations of course. So, for instance, in, in our experiments we have identified some features which are reminiscent of what is observed on idealize to these simulations, like drifting merging or
09:58:40 multi stability.
09:58:42 stability. But however it's hard for us to draw the comparisons between our experiments and those idealize simulations, namely because for instance the experiment is confined space especially, so the Jets are not free to free to evolve the friction is
09:58:58 So the Jets are not free to free to evolve the friction is small in our experiments, but it's not as some particularly small so we still stand in a regime which is strongly forced and strongly the spaceship which is not always the case in simulations.
09:59:10 And finally, in experiments we cannot reach the scale separation between the forcing and the Jets as large as we could want to. So we are a little bit limited beta.
09:59:25 So with these limitations and landing pages, there are several possibilities and questions that arise.
09:59:32 So if we keep in mind, only the baritone, etc. that are presented, what we could do now is to change it, it'll be the first thing we can change the first thing such that it occurs at a smaller scale, for instance, or switch to an even bigger experiment.
09:59:49 But then what question which is not really clear up to date is, is the scale of the first thing the scale separation between the first thing and the Jets really a key ingredient, and is it even really read event Joe physically, because it's a, it's hard
10:00:04 to reach experimentally.
10:00:07 We could switch to a forcing, which would be more chaotic, if we want to observe spontaneous transitions between the testable states that we have observed.
10:00:17 But then again, you would require a bigger experiment.
10:00:20 And we quit we can also, if, if we want to switch to higher to stronger forcing, and this we would be at the edge of dangerous trophy and we could study the finite was be number effects, which are potentially interesting.
10:00:37 And to conclude the next quite natural evolution for all of those experiments is to switch to a clinic setup and to, to build an analog of the weather layer, which is standing above digits.
10:00:54 So for instance, add fresh layer of fresh water, a jump of. They are deep layer of salt water and study the coupling between the stratified layer, and the deep layer and see for instance if we can.
10:01:05 If we can have analog of shadow vertices, coupled with the objects.
10:01:12 And that's it for me. Thank you.
10:01:23 Okay, thank you very much Daphne.
10:01:27 Are there any initial questions for Daphne john I still cannot raise my hand but I do have a question. And I'm very happy for you to ask you a question, even without raised hand.
10:01:41 Just wanted to as a definitely be zero, if they can push the results in terms of the mark number which came down and just before this transitions may be related to changes and
10:01:59 shared in my, my screen.
10:02:05 The transition that we observed. Whoops.
10:02:11 Well, I would just say it out loud doesn't work, you see my screen.
10:02:17 Yes.
10:02:19 The transition that we observe in our case it's due to the fact that the rugby waves which are directly forced by our small scale circulations become addicted by the normal flow, and the transition occurs when these words we waste our Facebook without
10:02:35 forcing windows zero flow exactly compensates for the, for the velocity of the westward propagating Ruby waves. That's the sonic condition that we find Jupyter to be in yet so that's that's the there's a link with a what what you you just presented in.
10:02:54 But the, the big difference with two parts of them is, is, is that we don't see stationary forcing on Jupiter do we.
10:03:04 Yeah so yeah that's of course that's the bigger the bigger the big problem so the problem is, you know, I don't know if we have data to know whether the first thing is propagating, and how is it propagating on Jupiter.
10:03:16 But if the first thing is not passively affected as soon as, as it is not passively addicted by the zoom of food, then you can have this kind of resonance to occur.
10:03:38 But of course if the first thing is just simply coupled with a normal flow you cannot have this resonance rocker because the waves with will always propagate with work, compared to I don't really know what the force in here, very long time scale so it
10:03:40 made the closet.
10:03:42 We call it a Princess and the Pea phenomenon that the troposphere on Jupiter those jets, which are talking to each other but they're also talking to the interior they may be able to sense, little p down there like The Princess and the Pea and lock onto
10:03:58 it.
10:03:58 This is how you know who is a princess.
10:04:00 Yeah.
10:04:05 Okay.
10:04:12 So,
10:04:11 so we've just that sound. That's great. I think that's perfectly timed were right about an hour.
10:04:17 So I'm going back to Bruce. Bruce, I'm kind of learning as we're going here. what's the next aspect of this session.
10:04:29 So what I'm is this is definitely a good time to take a break.
10:04:35 The question is whether or not we want to just continue in the next hour to have a discussion of the whole or whether it's worth subdividing into breakout rooms.
10:04:46 I think it's Sorry, I think we can keep us together I don't I'm not sure there's an advantage the group isn't that huge as well what I'm going to suggest is again, let's take a five minute break and if people just want to stick in their chat.
10:05:09 we'll just see how people want to proceed from there. But let's reconvene in five minutes at 10 past the hour. Does that sound good. Thanks all sounds good.
10:05:11 Sounds good to me.