| If
you know exactly what you are going to do, what is the point of doing
it? Pablo
Picasso He goeth furthest who knows not whither he is going. Oliver Cromwell Every line in your calculations ends with "=0". You are not making much progress! Kate Hammett We don't do the calculation because we don't know the answer, we do it because we have a conscience. Bryan Taylor Let's change the resolution on the Unknown. Gabe Plunk Let me put it differently: suppose we had a reactor... Per Helander Working together takes more than one person. Bill Dorland We can't do ultraviolence to that square bracket. Ian Abel Field lines are forever. Bryan Taylor This is not really an ill-posed problem, this is not a problem at all. Paul Dellar I am just doing mathematics at the moment, but it is mathematics that has some point. Bryan Taylor The equivalent of God in MAST is MHD, which is global and all-powerful. Anthony Field I've got a fishbone coming up. Tim Horbury We have crossed all the i's and dotted all the t's. Job's a good'un. Ian Abel Let us not jump in front of the bandwagon! Alex Schekochihin It's not the triviality, it's the emptiness of it that bothers me. Bryan Taylor Never take 0 for an answer. Alex Schekochihin This is a very inefficient way of achieving nothing. François Rincon We Hankel all the way in and then Hankel all the way out. Joseph Parker For the sake of fairness, let me mention that some people have objections to this, none of which are particularly valid. Chris Chen Yes, Steve, you have always known what we have only just figured out. Alfred Mallet This is more or less right. Perhaps less. Alfred Mallet You go ahead with your argument. I'll think. Steve Cowley Too simple? At the end of my talk, you will beg for simplicity! Andrey Beresnyak What is the point? The point is not the point! Anonymous This is why I am presenting this here and nowhere else: nothing is solved! Ian Abel This calculation is not intellectual masturbation: there's no orgasm. Anonymous |
It is
better to be vaguely right than exactly wrong. Carveth
Read (usually attributed to Maynard Keynes) Previous studies of this problem have been either unsatisfactory or limited in scope.---What is the difference between these?---This means either wrong or irrelevant. Anatoly Spitkovsky, Michael Medvedev & Steve Cowley (in conversation) I don't give a damn about astrophysics, explain to me what is going on. Anatoly Spitkovsky Have you subtracted the baby with the bathwater? Steve Balbus This is not rigour, unless you mean rigor mortis. Ian Abel I wouldn't say these are theoretical arguments... Let's just call them arguments. François Rincon You can never be too happy with the state of your closure. Amitava Bhattacharjee For this plot, 1 is 6.--- Weeell, not even. Steve Cowley & Steve Balbus This qualitative explanation is not of sufficient quality. Eugene Churazov If you mean it seriously, this is actually a very good question. Minhyong Kim This paper is a tour de farce. Ian Abel What is modelling? You run a simulation, you compare. If it coincides, great! If it doesn't coincide, fuck! Felix Parra We are stuck at x=0. Felix Parra I have seen papers where the student wasn't the problem. Michael Hardman There has been a lot of fascinating work on this subject, most of it kind of boring. Philipp Kempski So now you want us to drop everything we are doing and start worrying about what the big questions are?! Ian Abel Oh dear, I thought I had some conclusions. Nuno Loureiro I've got my little fingers inside this plasma. Steve Cowley Words will play a big role in this talk. Dmitri Uzdensky Everything that can be done should be done---and that's the astrophysical attitude. Michael Medvedev What I will talk about is not low-hanging fruit. A lot of people have looked at this. There is no fruit here at all.---How about sour grapes? Michael Medvedev & Nuno Loureiro In order to have a disappointment, you first have to have an appointment. Alex Schekochihin I can follow what you are doing here only in the broadest sense. Sir Steve Cowley In our experiment, we observed strong absence of magnetic energy. Archie Bott |
| Wk | Date |
Time
& place |
Speaker & Topic |
Background reading |
| -5 |
Tue Sept 1 |
9:00 ZOOM (link) |
Virtual Nordic Dynamo Seminar (organised by Axel Brandenburg) Jono Squire (Otago) --- In-situ switchback formation in the expanding solar wind |
ApJ 891, L2 (2020) |
| Wed Sept 2 |
16:00 ZOOM (sign up to get link) |
JPP Frontiers of Plasma Physics Colloquium
(organised by Bill
Dorland and Alex Schekochihin, chaird by Cary Forest) Miho Janvier (IAS, Paris) --- From observations of the solar corona to MHD simulations: a 3D standard model of solar flares |
JPP 83, 535830101 (2017) |
|
| Thu Sept 3 |
No seminar: EAB meeting for TDoTP (at 13:00). |
|||
| -4 |
Tue Sept 7 |
14:00 ZOOM (link) |
Virtual Nordic Dynamo Seminar (organised by Axel Brandenburg) Archie Bott (Princeton) --- Inefficient magnetic-field amplification in supersonic laser-plasma turbulence |
arXiv:2008.06594 |
| Wed Sept 9 |
16:00 ZOOM (sign up to get link) |
JPP Frontiers of Plasma Physics Colloquium
(organised by Bill
Dorland and Alex Schekochihin, chaired by Bill Dorland) Lina Hadid (LPP, Ecole Polytechnique) --- Turbulent energy cascade rate in the Earth's magnetosheath and the solar wind using in-situ spacecraft data |
||
| Thu Sept 10 |
11:00 ZOOM Alex for link) |
Plasma
Group Meeting (organised
by MICHAEL) Nicolas Christen --- Studies of NBI-driven rotation using the local gyrokinetic code GS2 |
||
| -3 |
Wed Sept 16 |
16:00 ZOOM (sign up to get link) |
JPP Frontiers of Plasma Physics Colloquium
(organised by Bill
Dorland and Alex Schekochihin, chaired by Cary Forest) Eve Stenson (IPP, Greifswald) --- En route to magnetically confined matter-antimatter plasmas |
|
| Thu Sept 17 |
11:00 ZOOM Alex for link) |
Plasma
Group Meeting/Journal Club (organised
by ALEX) Alex Schekochihin --- Some idle musings on decaying (R)MHD turbulence [Note: in addition, and as a background, to the papers posted in the box on the right, I strongly recommend Chapters 11, 16 & 18 from P. A. Davidson, Turbulence in Rotating, Stratified and Electrically Conducting Fluids, (CUP 2013). This is a highly readable master class in the theory of decaying turbulence, both hydro and MHD. If you want a copy, email me. Most of the material is also available in his own original papers in JFM (just search), but the book is an excellent and detailed review of those, as well as of the "classical" literature.] |
JPP 86, 535860401 (2020) PRD 70, 083009 (2004) PLB 398, 321 (1997) ++Typed notes from author on request |
|
| -2 |
Wed Sept 23 |
16:00 ZOOM (sign up to get link) |
JPP Frontiers of Plasma Physics Colloquium
(organised by Bill
Dorland and Cary Forest) Cary Forest (UW Madison) --- The Wisconsin HTS Axisymmetric Mirror (WHAM) on a faster path to lower cost fusion energy |
|
| Thu Sept 24 |
11:00 ZOOM Alex for link) |
Plasma Journal Club (organised
by BENCE) We will discuss this paper: arXiv:2007.08471 (Gruzinov et al., The thermodynamics of rotating black-hole star clusters) and related issues (see links to additional reading the box on the right) --- introduced by Bence Kocsis, just arrived to join TP as a new faculty member in Galactic Dynamics |
J. Phys. A 47, 292001 (2014) ApJ 842, 90 (2017) PRL 123, 021103 (2019) |
|
| -1 |
Mon Sept 28 |
11:00 ZOOM Felix for link) |
Plasma Group Meeting (organised
by FELIX) Juan Ruiz Ruiz & Valerian Chen --- rehearsal for invited talks at CIEMAT on DBS modelling |
|
| Wed Sept 30 |
16:00 ZOOM (sign up to get link) |
JPP Frontiers of Plasma Physics Colloquium
(organised by Bill
Dorland and Alex Schekochihin, chaired by Alex Schekochihin) Elena Amato (Arcetri) --- Some recent puzzles on the acceleration and transport of Galactic Cosmic Rays |
||
| Thu Oct 1 |
11:00 ZOOM Alex for link) |
Plasma Journal Club (organised
by MICHAEL HARDMAN) We will discuss the papers, and the issues, arising from the Royal Society meeting "Fusion energy using tokamaks: can development be accelerated?" The papers are here. |
||
| 16:00 ZOOM (sign up to get link) |
Special JPP Frontiers of Plasma Physics Colloquium
(organised by Bill
Dorland and Cary Forest, chaired by Alex Schekochihin) Alex Creely (MIT) --- Overview of the SPARC tokamak Pablo Rodriguez-Fernandez (MIT) --- Predictions of core plasma performance for the SPARC tokamak Ryan Sweeney (MIT) --- MHD stability and disruptions in the SPARC tokamak |
JPP Special Issue with 7 papers on SPARC |
||
| 0 |
Georgia
Acton, Robbie Ewart, & Silvia Trinczek join the group as DPhil
students (advised by Michael Barnes, Alex Schekochihin, and Felix
Parra, respectively);
Plamen Ivanov & Jason Parisi are set to graduate this term and
become Culham Fusion Research Fellows; Bence Kocsis joins TP as
Associate Professor in Theoretical Astrophysics (Galactic Dynamics). |
|||
| Wed Oct 7 |
16:00 ZOOM (sign up to get link) |
JPP Frontiers of Plasma Physics Colloquium
(organised by Bill
Dorland and Cary Forest) Paulo Alves (Stanford--->UCLA) --- Accelerating our understanding of complex nonlinear plasma phenomena using machine learning |
||
| Thu Oct 8 |
11:00 ZOOM Alex for link) |
Plasma Group Meeting (organised
by ALEX) Robbie Ewart --- Modelling the shallow-angle magnetic presheath with non-adiabatic electrons |
preprint from author on request |
|
| I |
Wed Oct 14 |
16:00 ZOOM (sign up to get link) |
JPP Frontiers of Plasma Physics Colloquium
(organised by Bill
Dorland and Cary Forest) Jeff Parker (LLNL--->UW Madison) --- Topological phase in plasmas |
arXiv:1909.07910 arXiv:2009.06026 |
| Thu Oct 15 |
11:00 ZOOM Alex for link) |
Plasma Seminar (organised
by ALEX) Romain Meyrand & Jono Squire (U of Otago, NZ) --- Violation of the zeroth law of turbulence in space plasmas |
arXiv:2009.02828 | |
| II |
Mon Oct 19 |
15:00 ZOOM Michelle for link) |
ALP Seminar (organised
by Peter Norreys) James Sadler (LANL) --- Improved transport coefficients for collisional magnetized plasma The Braginskii transport
coefficients describe the flow of heat and magnetic field in a
collisional magnetized plasma. Even if the magnetic pressure is far
less than the plasma pressure, magnetic fields can deflect and insulate
the heat flow, indirectly altering the hydrodynamics. The magnetic
field is also enhanced and advected by the heat flow. We show that many
magneto-hydrodynamic (MHD) simulations have used a set of transport
coefficients that yield an unphysical discontinuity in advection
velocity. Here we use a kinetic Fokker-Planck approach to find new fit
functions that rectify this issue and we describe a new MHD instability
that results. It turns out that these re-definitions also bring out the
symmetry of the transport coefficients and the thermal and magnetic
transport that they describe.
|
|
| Wed Oct 21 |
16:00 ZOOM (sign up to get link) |
JPP Frontiers of Plasma Physics Colloquium
(organised by Bill
Dorland and Alex Schekochihin) Stuart Bale (Berkeley) --- Parker Solar Probe at the edge of the streamer belt |
||
| Thu Oct 22 |
11:00 ZOOM Alex for link) |
Plasma
Group Meeting (organised
by ALEX) Plamen Ivanov --- Report from the Varenna Conference |
||
| III |
Mon Oct 26 |
11:30 ZOOM Michelle for link) |
ALP Seminar (organised
by Peter Norreys) Michael Bonitz (Kiel) --- Perspectives of quantum plasma and warm dense matter theory Presently we are
witnessing dramatic progress in experiments with dense quantum plasmas
where matter is being compressed to densities exceeding that of
conventional solids. This gives rise to a complicated mix of condensed
matter and plasma phases with unknown properties. At the same time,
accurate laser and x-ray based diagnostic tools have emerged that probe
the properties of such warm dense matter [1]. To understand these
experiments and predict new ones poses a challenge to theory and
simulations. Promising tools include generalized quantum hydrodynamics
[2,3] and quantum kinetic equations [4]. We will discuss some of the
recent theory developments and present accurate results for the
electron dynamic structure factor [5] and for the plasmon dispersion in
dense quantum plasmas [6].
[1] M. Bonitz et al., Phys. Plasmas 27, 042710 (2020) [2] M. Bonitz et al., Phys. Plasmas 26, 090601 (2019) [3] Zh. Moldabekov et al., Phys. Plasmas 25, 031903 (2018) [4] M. Bonitz, Quantum Kinetic Theory, 2nd ed. Springer 2016 [5] T. Dornheim et al., Phys. Rev. Lett. 121, 255001 (2018) [6] P. Hamann, Contrib. Plasma Phys., in press (2020), arXiv:2008.04605 |
|
| Wed Oct 28 |
15:00 ZOOM (sign up to get link) |
JPP Frontiers of Plasma Physics Colloquium
(organised by Bill
Dorland and Alex Schekochihin, chaired by Cary Forest) Eliot Quataert (Princeton) --- The physics of galaxy cluster plasmas |
||
| Thu Oct 29 |
11:00 ZOOM Alex for link) |
Plasma
Group Meeting (organised
by FELIX) Jason Parisi --- Parisi modes strike back |
||
| IV |
Wed Nov 4 |
16:00 ZOOM (sign up to get link) |
JPP Frontiers of Plasma Physics Colloquium
(organised by Bill
Dorland and Alex Schekochihin) Louise Willingale (UM Ann Arbor) --- Magnetic signatures of radiation-driven double ablation fronts |
PRL 125, 145001 (2020) |
| Thu Nov 5 |
11:00 ZOOM Alex for link) |
Plasma
Group Meeting (organised
by FELIX) Felix Parra --- Rarefaction wave train driven by Bohm and Chodura conditions |
preprint from author on request |
|
| V |
9-13 Nov |
APS DPP Virtual Meeting |
||
| Thu Nov 12 |
11:00 ZOOM Alex for link) |
Plasma Journal Club (organised
by MICHAEL HARDMAN) We will discuss this paper: arXiv:2010.14839 (Di Siena et al., New high-confinement regime with fast ions in the core of fusion plasmas) |
NF 58, 054002 (2018) |
|
| VI |
Wed Nov 18 |
16:00 ZOOM (sign up to get link) |
JPP Frontiers of Plasma Physics Colloquium
(organised by Bill
Dorland and Alex Schekochihin) Ahmed Diallo (Princeton) --- Characterizing and understanding the instabilities localised in the edge of fusion devices to improve pedestal predictive models |
|
| Thu Nov 19 |
11:00 ZOOM Alex for link) |
Plasma
Group Meeting (organised
by ALEX) Toby Adkins, David Hosking, Juan Ruiz, Denis St-Onge --- Report from APS DPP Meeting |
||
| VII |
Mon Nov 23 |
11:30 ZOOM Michelle for link) |
ALP Seminar (organised
by Peter Norreys) Petros Tzeferacos (Rochester) --- Concerted simulations and laser-driven laboratory experiments to shed light on fundamental physical processes in plasma astrophysics I present an overview of
the exciting fundamental science in magnetized astrophysical plasmas
that the TDYNO team is accomplishing through concerted application of
the FLASH code and laboratory plasma astrophysics experiments. Our
international collaboration, co-lead by the University of Oxford and
the Flash Center for Computational Science, has conducted recent
breakthrough experiments in the study of turbulent dynamo. This
ubiquitous astrophysical mechanism is thought to be responsible for
present-day magnetization of numerous celestial objects but had eluded
laboratory plasma physicists for decades. The experiments have enabled
us to explore dynamo in various regimes, providing us with novel
insights and a new tool to validate or falsify our theoretical
understanding. I will also describe how these experiments are enabling
laboratory investigations of cosmic ray (CR) acceleration, the
diffusive transport of extragalactic and ultra-high energy CRs, and the
strong suppression of heat conduction in galaxy clusters.
|
Nature Comm. 9, 591 (2018) ApJ 892, 114 (2020) arXiv:2007.12837 |
| Thu Nov 26 |
11:00 ZOOM Alex for link) |
Plasma
Group Meeting (organised
by ALEX) David Hosking --- Not-so-idle musings on decaying MHD turbulence |
arXiv:2010.00699 (sec 11) + complete revision of above in a preprint from author on request |
|
| VIII | Wed Dec 2 |
16:00 ZOOM (sign up to get link) |
JPP Frontiers of Plasma Physics Colloquium
(organised by Bill
Dorland and Alex Schekochihin) James Drake (Maryland) --- Whistler-regulated MHD: Transport equations for electron thermal conduction in the high-beta intracluster medium of galaxy clusters |
arXiv:2007.07931 |
| Thu Dec 3 |
11:00 ZOOM Alex for link) |
Plasma
Group Meeting (organised
by ALEX) Open mic |
||
| 9 | Wed Dec 9 |
16:00 ZOOM (sign up to get link) |
JPP Frontiers of Plasma Physics Colloquium
(organised by Bill
Dorland and Alex Schekochihin) Ellen Zweibel (UW Madison) --- Some open questions in the plasma physics of cosmic rays |
|
| Thu Dec 10 |
11:00 ZOOM Alex for link) |
Plasma Group Meeting (organised
by MICHAEL HARDMAN) Open mic |
||
| 10 | Wed Dec 16 |
16:00 ZOOM (sign up to get link) |
JPP Frontiers of Plasma Physics Colloquium
(organised by Bill
Dorland and Alex Schekochihin) Frank Jenko (IPP Garching) --- When will we be able to predict plasma confinement in fusion devices? |
|
| Thu Dec 17 |
11:00 ZOOM Alex for link) |
Plasma Seminar (organised
by MICHAEL HARDMAN) Paulo Rodrigues (IST Lisbon) --- Alfven eigenmodes and fast ions in tokamaks |
||
| Thu Dec 24 |
No seminar. Merry Christmas! |
|||
| Thu Dec 31 |
No seminar. Happy New Year! (it can hardly be worse than 2020...) |
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