Seminars Hilary Term of 2025

PLASMA SEMINARS AND GROUP MEETINGS

The style of the seminars will be informal/chaotic/interactive, following the established tradition. The format of the presentations can be a tutorial on a topic of interest, a report on just completed/ongoing/just starting/potentially interesting research projects, a literature review, a lecture by a passing visitor or anything else worthwhile that anyone cares to suggest. The speakers will be interrupted freely and asked to defend themselves. For background reading, only the most relevant or the most recent references are posted; please follow the paper trail from there. The schedule is subject to change on short notice, but what you see posted here is always up to date; the seminars are also announced via the department's seminar server (group meetings are not). Please email Alex Schekochihin if you would like to receive email updates on these seminars. "Plasma group meetings (or journal clubs)" will discuss current affairs (ongoing projects, new litearture etc.) as well as feature some presentations that are even more informal than seminars. They are open to all members of the Oxford Plasma Theory Group. While some expected contributions are pre-announced, everything is TBC and people wishing their work to be discussed can volunteer contributions without prior notice. Unlike for the seminars, there will not be full-spam-list email reminders of the group meetings. The seminars and group meetings are organised by Michael Barnes and Alex Schekochihin, please contact them with any queries or if you wish to present something.

Past seminar database: Autumn 2007; Winter-Spring 2008; Summer 2008; Autumn 2008; HT 2009; TT 2009; Summer 2009; MT 2009; HT 2009; TT 2010; Summer 2010; MT 2010; HT 2011; TT 2011; Summer 2011; MT 2011; HT 2012; TT 2012; Summer 2012; MT 2012; HT 2013; TT & Summer 2013; MT 2013; HT 2014; TT & Summer 2014; MT 2014; HT 2015; TT & Summer 2015; MT 2015; HT 2016; TT & Summer 2016; Autumn/MT 2016; HT 2017; TT & Summer 2017; Autumn/MT 2017; HT 2018; TT & Summer 2018; MT 2018; HT 2019; TT & Summer 2019; MT 2019; HT 2020; TT & Summer 2020; MT 2020; HT 2021; TT & Summer 2021; Autumn/MT 2021; HT 2021; TT & Summer 2022; Autumn/MT 2022; HT 2023; TT & Summer 2023; Autumn/MT 2023; HT 2024; TT & Summer 2024; Autumn/MT 2024;

Hilary Term of 2025

The seminars/group meetings will be on Tuesday at 14:00 in the Simpkins Lee Room, Beecroft Building, except where indicated otherwise below, in red.
It will be possible to join these meetings (when they are held in SL Room) on ZOOM --- details available from Alex on request.
Those who join these meetings on ZOOM are asked keep their video cameras on.
The ZOOM system in Simpkins Lee Room does not display a list of participants whose cameras are off. It is not germane to these informal meetings to have invisible listeners of whom those present in the room are unaware, so if you are unable or unwilling to turn on your camera, you cannot join the meeting.
Here is a list of all Physics seminars.

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
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
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. Francois Rincon
For the sake of fairness, let me mention that some people have objections to this, none of which are particularly valid. Chris Chen
This is more or less right. Perhaps less. Alfred Mallet
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
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. Francois Rincon

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

It is better to be vaguely right than exactly wrong. Carveth Read (usually attributed to Maynard Keynes)

What is modelling? You run a simulation, you compare. If it coincides, great! If it doesn't coincide, fuck! 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.---What about sour grapes? Michael Medvedev & Nuno Loureiro
In order to have a disappointment, you first have to have an appointment. Alex Schekochihin
In our experiment, we observed strong absence of magnetic energy. Archie Bott
Much as I somewhat hate this approach... Peter Davidson
Your infinity is my zero. Mantas Abazorius
If I had known the outcome of this calculation, I would never have done it. Michael Hardman

Now that everyone knows this is the new Pandora's box, they are all going to jump into it. Francois Rincon
We must think outside the axisymmetric box. Georgia Acton

This is not real, it's a Platonic absolute.---The real thing is more Platonic and more absolute. Alex Schekochihin & Anthony Field
All I've done here is sacrificed equality in favour of inequality. Per Helander
Generally, it depends. Steve Majeski
This numerical scheme works fine, but it is physically disgusting. Bruno Despres
This research is not only not finished, it has not really been started. Anatoly Spitkovsky
This is what really matters... given that "really matters" is a strong word in this context. Robbie Ewart
This was discovered accidentally, but it was an informed accident. Plamen Ivanov
Infinity is a long way away. Rafael Bailo
To solve the kinetic equation on a mesh, you really need to know what you are doing.
That's why, historically, people haven't. Rafael Bailo
Just shout if you want to chat. Robbie Ewart
They ran this simulation for a long time but not forever. Patrick Reichherzer

[these quotes are mostly from these seminars and the Vienna meetings]

Wk	Date	Time & place	Speaker & Topic	Background reading	Visitors in town
	Tue 7 Jan	14:00 SL Room & ZOOM (ask Alex for link)	Plasma Journal Club (organised by ALEX) 1) Robin Greif will discuss Ingelsten et al. "Data-driven discovery of a heat flux closure for electrostatic plasma phenomena" 2) Patrick Reichherzer will discuss "Observation of a spectral hardening in cosmic ray boron spectrum with the DAMPE space mission"	1) arXiv:2411.18358 2) arXiv:2412.11460 additional AI papers: arXiv:2405.13232 NF 65, 016015 (2024) CEA hal-04855224v1
0	Tue 14 Jan	14:00 SL Room & ZOOM (ask Alex for link)	Plasma Journal Club (organised by ALEX) 1) Archie Bott will discuss Walsh et al. "Magnetized ICF implosions: non-axial magnetic field topologies" 2) Juan Ruiz will discuss Chen et al. "The effects of zonal fields on energetic-particle excitations of reversed-shear Alfven eigenmode: simulation and theory"	1) arXiv:2411.10538 2) NF 65, 016018 (2025)	Stephane Colombi (IAP)
I	Tue 21 Jan	14:00 SL Room & ZOOM (ask Alex for link)	Plasma Seminar (organised by BARRY) Stephane Colombi (IAP) --- Some numerical aspects of the Vlasov-Poisson equations In the concordance model of the formation of large-scale structures in the Universe, the distribution of matter is dominated by a dark component that can be approximated by a self-gravitating, collisionless fluid, the dynamics of which is described by the Vlasov-Poisson equations. I will study some properties of these equations and how they are solved numerically with the traditional N-body method and direct solvers using ``semi-Lagrangian" methods and sophisticated computational geometry techniques. Focusing here on the dynamical evolution of single objects, I will study what happens for various systems, evolving from an initially warm or initially cold state. The concept of mean field limit will be approached through comparisons between N-body and Vlasov codes that will show that it is sometimes difficult, if not nearly impossible, to disentangle numerical effects from physical effects.	MNRAS 441, 2414 (2014) A&A 647, A66 (2021)	Stephane Colombi (IAP) Sasha Migdal (IAS)
I	Wed 22 Jan	14:00 Freeman Room & ZOOM (ask Alex for link)	Special Turbulence Seminar (organised by ALEX) Sasha Migdal (IAS) --- An exact solution to the Navier-Stokes equations for decaying turbulence: universal results from first principles Decaying turbulence, characterized by energy dissipation from an initial high-energy state, remains a fundamental challenge in classical physics. This work presents an exact analytical solution to the Navier-Stokes (NS) equations for incompressible fluid flow in the context of decaying turbulence, introducing the novel framework of the Euler ensemble. This framework maps turbulent dynamics onto discrete states represented by regular star polygons with rational vertex angles in units of 2pi. A key feature of the Euler ensemble is a duality between classical turbulence and a hidden one-dimensional quantum system, analogous to the AdS/CFT correspondence in quantum field theory. This duality enables the derivation of exact turbulence statistics, replacing traditional heuristic scaling laws with universal results derived directly from the NS equations. For example, the decay law for turbulent kinetic energy is predicted as E(t)~t^{-5/4}, with quantitative agreement to within 1% standard deviation in experimental and numerical data. The framework is validated using Direct Numerical Simulations (DNS) and experimental results, including grid turbulence and large-tank experiments. Additionally, the Euler ensemble predicts novel macroscopic quantum-like effects, such as oscillations in the decay index as a function of the scaling variable r/\sqrt{t}. These predictions highlight new avenues for experimental and numerical exploration of turbulence. This work addresses long-standing challenges in turbulence theory, providing a rigorous, universal description of decaying turbulence with applications across fluid dynamics, geophysics, and engineering.	arXiv:2411.01389 arXiv:2304.13719 slides	Stephane Colombi (IAP) Sasha Migdal (IAS)
II	Tue 28 Jan	14:00 SL Room & ZOOM (ask Alex for link)	Plasma Tutorial (organised by ALEX) Sergei Sharapov (UKAEA) --- Fast ion physics, Part I
III	Tue 4 Feb	14:00 SL Room & ZOOM (ask Alex for link)	Plasma Tutorial (organised by ALEX) Sergei Sharapov (UKAEA) --- Fast ion physics, Part II
IV	Tue 11 Feb	14:00 SL Room & ZOOM (ask Alex for link)	Plasma Seminar (organised by MICHAEL HARDMAN) James Cook (UKAEA) --- TBA/TBC
V	Tue 18 Feb	14:00 SL Room & ZOOM (ask Alex for link)	Plasma Journal Club (organised by ALEX) 1) Will Clarke will discuss Arro et al. "Spatio-temporal energy cascade in three-dimensional magnetohydrodynamic turbulence" 2) Michael Nastac will discuss Vanthieghem & Levinson "Relativistically magnetized collisionless shocks in pair plasma: I. Solitons, chaos, and thermalization"	1) arXiv:2411.19927 2) arXiv:2411.16484	Dustin Froula (Rochester) Hagai Perets (Technion)
VI	Tue 25 Feb	14:00 SL Room & ZOOM (ask Alex for link)	Plasma Group Meeting (organised by ALEX) Felix Parra (Princeton) --- TBA		Felix Parra (Princeton)
VII	Tue 4 Mar	14:00 SL Room & ZOOM (ask Alex for link)	Plasma Seminar (organised by ALEX) Jonathan Citrin (Google Deep Mind) --- TBA		Jonathan Citrin (Google Deep Mind)
VIII	Tue 11 Mar	14:00 SL Room & ZOOM (ask Alex for link)	Plasma Seminar (organised by ALEX) Uddipan Banik (IAS, Princeton) --- TBA		Uddipan Banik (IAS)
9	Tue 18 Mar	14:00 SL Room & ZOOM (ask Alex for link)	Plasma Group Meeting (organised by ALEX) TBA
	Tue 25 Mar	14:00 SL Room & ZOOM (ask Alex for link)	Plasma Group Meeting (organised by ALEX) TBA
	Tue 1 Apr	14:00 SL Room & ZOOM (ask Alex for link)	Plasma Group Meeting (organised by ???) TBA
	Tue 8 Apr	14:00 SL Room & ZOOM (ask Alex for link)	Plasma Group Meeting (organised by ???) TBA
	Tue 15 Apr	14:00 SL Room & ZOOM (ask Alex for link)	Plasma Group Meeting (organised by ???) TBA --- Report from the 2025 Sherwood Fusion Theory Conference
0	Tue 22 Apr	14:00 SL Room & ZOOM (ask Alex for link)	Plasma Group Meeting (organised by ALEX) TBA
0	Plamen Ivanov returns to Oxford to join the research staff at UKAEA; he will be a permanent visitor at Oxford

Trinity Term of 2025