Seminars Trinity Term & Summer of 2024

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;

Trinity Term & Summer of 2024

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
0	Tue 16 Apr	14:00 SL Room & ZOOM (ask Alex for link)	Plasma Seminar (organised by MICHAEL HARDMAN) Michael Basile (ONERA/Ecole Polytechnique) --- Semi-Lagrangian non-interpolating schemes for plasma modelling The property of Semi-Lagrangian Schemes to remove the CFL condition in hyperbolic PDEs has led these schemes to successful applications in Plasma Physics. However, standard semi-Lagrangian methods primarily introduce numerical diffusion due to interpolation and pose challenges in parallelization, especially when employing global interpolation schemes. An alternative formulation of Semi-Lagrangian methods was proposed by Ritchie in 1986, introducing Non-Interpolating Semi-Lagrangian methods for meteorological models. This work has expanded upon Ritchie's formulation, developing numerical schemes for plasma modeling. Starting with a Vlasov-Poisson model, it has been possible to perform simulations with high CFL values while maintaining the validity of the physics in classical experiments, such as Landau damping. The study ends with the application of NISL to a Plasma Sheath Formation model. This achievement is reached by using RK integrators and WENO (Weighted Essentially Non-Oscillatory) discretization techniques. This method proves particularly effective for simulating Sheath Formation in plasma, a task complicated by strong gradients due to the diverging electric field, which challenge many numerical solvers.	thesis	Michael Basile (ONERA/EP)
I	Tue 23 Apr	14:00 SL Room & ZOOM (ask Alex for link)	Plasma Seminar (organised by ALEX) Ben Chandran (UNH) --- The gyrokinetic dispersion relation of microtearing modes in collisionless toroidal plasmas	JPP 90, 905900204 (2024)	Ben Chandran (UNH)
II	Tue 30 Apr	14:00 SL Room & ZOOM (ask Alex for link)	Plasma Group Meeting (organised by ARCHIE) Archie Bott --- Firehose-induced collisionality in weakly collisional magnetised plasmas	PRL 112, 205003 (2014) ApJL 922, L35 (2021) arXiv:2310.17754 +ask author for preprint	Ben Chandran (UNH)
III	Tue 7 May	14:00 SL Room & ZOOM (ask Alex for link)	Plasma Group Meeting (organised by ALEX) 1) Anjor Kanekar (Radiant AI) --- Things I would do differently (than I did in my PhD, before working in tech/AI) 2) Report from the PCTS Meeting on particle transport in magnetised turbulence (led by Robbie Ewart)	blog paper PhD thesis (2014) JPP 81, 305810104 (2015)	Ben Chandran (UNH) Anjor Kanekar (Radiant AI)
IV	Tue 14 May	14:00 SL Room & ZOOM (ask Alex for link)	Plasma Journal Club (organised by ALEX) 1) Plamen Ivanov will discuss Volcokas et al. "Self-interaction of turbulent eddies in tokamaks with low magnetic shear" 2) Robbie Ewart will discuss Lemoine et al. "Nonlinear aspects of stochastic particle acceleration"	arXiv:2404.14520 PRD 109, 063006 (2004)	Ben Chandran (UNH)
V	Tue 21 May	14:00 SL Room & ZOOM (ask Alex for link)	Plasma Seminar (organised by ALEX) Alexander Mushtukov (Oxford Astro) --- Accretion onto strongly magnetised neutron stars: recent results and issues
VI	Tue 28 May	14:00 SL Room & ZOOM (ask Alex for link)	Plasma Journal Club (organised by ALEX) Experimental fusion physics galore... 1) Plamen Ivanov will discuss Choi et al. "Mesoscopic transport in KSTAR plasmas: avalanches and the ExB staircase" and Long et al. "On how structures convey non-diffusive turbulence spreading" 2) Juan Ruiz will discuss Ajay CJ et al. "Gyrokinetic investigation of toroidal Alfven eignenmode turbulence" and Ding et al. "A high-density and high-confinement tokamak plasma regime for fusion energy"	PPCF, accepted NF 4, 064002 (2024) arXiv:2404.18910 Nature 629, 555 (2024)
VII	Tue 4 June	14:00 SL Room & ZOOM (ask Alex for link)	Plasma Seminar (organised by ROBBIE) James Matthews (Oxford Astro) --- Ultrahigh-energy cosmic rays: an origin story ...followed by Plasma Journal Club (organised by ALEX) Patrick Reichherzer will discuss Vega et al. "Particle acceleration in relativistic Alfvenic turbulence"	ECRS Proc. (2023) MNRAS 524, 631 (2023) MNRAS 511, 448 (2022) MNRAS 482, 4303 (2019) MNRAS 479, L76 (2018) arXiv:2405.07891
VIII	Tue 11 June	14:00 SL Room & ZOOM (ask Alex for link)	Plasma Journal Club (organised by ALEX) 1) Michael Nastac will discuss Stumpo et al. "Relating intermittency and inverse cascade to stochastic entropy in solar wind turbulence" --- this paper will be used as context for a broader discussion of entropy and stochasticity; some background reading links are posted on the right 2) Barry Ginat will discuss Son and Stephanov "Relativistic guiding-center motion: action principle, kinetic theory, and hydrodynamics" 3) Michael Hardman will discuss Magee et al. "Direct observation of ion acceleration from a beam-driven wave in a magnetic fusion experiment" --- with a proposal for further action	ApJL 959, L20 (2023) ARCMP 2, 329 (2011) PRF 5, 034602 (2020) arXiv:2405.08073 Nature Phys. 15, 281 (2019)
9	Tue 18 June	14:00 SL Room & ZOOM (ask Alex for link)	Plasma Group Meeting & Journal Club (organised by ALEX) Robin Greif will discuss Clavier et al. "A generative machine learning surrogate model of plasma turbulence" ...followed by a short presentation of his recent work on using ML to enable efficient scanning of 17th- and 18th-century German manuscripts, in collaboration with researchers in digital humanities.	arXiv:2405.13232
	Fri 21 June	11:30 SL Room	Special Atomic & Laser Physics Seminar (organised by S. Hooker): Karl Krushelnick (U of Michigan, Ann Arbor) --- The ZEUS Petawatt laser facility and high field science research at the University of Michigan The Zettawatt Equivalent Ultrashort pulse laser System (ZEUS) is a National Science Foundation-funded user facility located at the University of Michigan in the US. The laser will be capable of producing 3-Petawatt pulses and can also be split to create synchronized 2.5-PW and 0.5-PW pulses. This presentation will describe the different capabilities of the facility available to users in each of the three target areas and the current laser status and recent results on laser wakefield acceleration and x-ray generation. Results from other recent experiments on magnetic field dynamics from intense laser produced plasmas will also be discussed.
	Atharva Mahajan (Oxford Physics 2nd year) joins the group as a summer intern to work with Michael Barnes
	Tue 25 June	14:00 SL Room & ZOOM (ask Alex for link)	Plasma Journal Club (organised by JUAN & PLAMEN) We discussed Carralero et al. "First experimental observation of zonal flows in the optimized stellarator Wendelstein 7-X"	arXiv:2406.12514
	Wed 3 July	14:00 Freeman Rm	Plasma Seminar (organised by ALEX) Toby Adkins (Otago) --- What role do electrons play in helicity-barrier-mediated turbulence?	arXiv:2404.09380 ApJ 957, L30 (2023) Nature Astron. 6, 715 (2022) JPP 87, 535870301 (2021)	Toby Adkins (Otago) Luis Silva (IST Lisbon)
	Surui Li (Cambridge NatSci 2nd year) joins the group as a summer intern to work with Archie Bott & Alex Schekochihin				Toby Adkins (Otago) Luis Silva (IST Lisbon)
	Tue 9 July	14:00 Freeman Rm	Plasma Group Meeting (organised by MICHAEL BARNES) Megan Evans --- Exploring bistability in toroidal systems with magnetic and flow shear A previous study [1] saw bistability in the code GS2. However gyrokinetic codes are both difficult to interpret and require many CPU hours per simulation, and it is thought that this may be alleviated by using a fluid code such as in [2]. Ivanov's model has been modified to include both flow and magnetic shear, transformed into a frame such that the flow and magnetic shear undo each other, as in [3], so that in 2D the magnetic drifts are time-dependent. A 2D fluid code is then modified to include this, and benchmarked. Relevant papers linked; in [4], secs 2.1-2.6 are most important.	[1] JPP 88, 905880504 (2022) [2] JPP 86, 855860502 (2020) [3] PPCF 52, 125001 (2010) [4] JPP 88, 905880402 (2022)	Luis Silva (IST Lisbon)
	Enrico Maritnez (Oxford Physics 2nd year) joins the group as a summer intern to work with Michael Barnes				Luis Silva (IST Lisbon)
	Tue 16 July	14:00 Freeman Rm	Plasma Seminar (organised by GEORGIA) Hanne Thienpondt (CIEMAT) --- Gyrokinetic turbulence in stellarators: overview of fundamental concepts	arXiv:2404.09929 PRR 5, L022053 (2023)	Luis Silva (IST Lisbon) Hanne Thienpondt (CIEMAT)
	Tue 23 July	14:00 Freeman Rm	Plasma Group Meeting (organised by MICHAEL BARNES) Open mic		Hanne Thienpondt (CIEMAT) Francois Rincon (Toulouse)
	29 July-1 Aug	All Day DWB	Special conference to celebrate Steve Balbus's 70th birthday (organised by C. Terquem) Making waves and instabilities: The excellent adventures of Steve Balbus in space		Matt Kunz, David Hosking (Princeton) Francois Rincon (Toulouse) +many others
	Shuzhe Ren (Oxford Physics 2nd year) joins the group as a summer intern to work with Patrick Reichherzer & Alex Schekochihin
	Tue 6 Aug	14:00 Freeman Rm	Plasma Group Meeting (organised by PRAKRITI) TBA
	Mon 12 Aug	10:30 Freeman Rm	Solar Wind Discussion Meeting (organised by ALEX) This meeting will feature a broad discussion of solar-wind/space plasmas: new data and theory challenges. Informal discussions will continue all day on 12 & 13 August, in Freeman Room. All those who wish to participate are welcome. Talks will not necessarily be in the order listed below. 1) Chris Chen (Queen Mary) --- Recent results on solar-wind turbulence and kinetic physics 2a) Tim Horbury (Imperial) --- Ion-scale isolated structures: drivers of the turbulent cascade? 2b) " --- Future missions 3) Fouad Sahraoui (Ecole Polytechnique) --- Ion vs. electron heating: theory and MMS data 4) Michael Nastac (Oxford) --- Universal fluctuation spectrum of Vlasov-Poisson turbulence 5) Robbie Ewart (Oxford) --- Relaxation to universal non-Maxwellian equilibria 6) Toby Adkins (Otago, on zoom) --- Helicity barrier: executive summary 7) Michael Zhang (Princeton) --- Dependence of extreme minor-ion heating on beta and imbalance in Alfvenic turbulence 8) Archie Bott (Oxford) --- Firehose instability in collisionless plasma Some additional reading that arose in discussions: Small-scale Alfven waves: Mallet+ arXiv:2303.10192 PSP results summary: SSR 219, 8 (2023) Magneto-immutability: Squire+ JPP 89, 905890417 (2023); Majeski+ arXiv:2405.02418 PSP E-field instrument: website, Bale+ SSR 204, 49 (2016) Electron holes: Liu+ ApJ 899, L31 (2020), Wang+ JGR 125, e2020JA028386 (2020), Huang+ JGR 122, 8577 (2017), ApJ 861, 29 (2018)	1) arXiv:2407.10815 ApJ 957, 111 (2023) A&A 686, A238 (2024) JPP 88, 175880502 (2022) ApJ 941, 176 (2022) A&A 672, L4 (2023) 2a) JGR 111, A10106 (2006) + preprint on request PSP: SSR 219, 8 (2023) 3) ApJ 923, 122 (2021) PRL 130, 205201 (2023) PRL 132, 235201 (2024) 4) PRE 109065210 (2024) + preprint on request 5) JPP 89, 905890516 (2023) + preprint on request 6) arXiv:2404.09380 7) arXiv:2408.04703 8) ApJ 922, L35 (2021) + preprint on request	Chris Chen (Queen Mary) Tim Horbury (Imperial) Fouad Sahraoui (Ecole Polytechnique) Michael Zhang (Princeton) Ian Abel (Maryland)
	Tue 13 Aug	10:30 & 14:00 Freeman Rm
	Tue 20 Aug	14:00 Freeman Rm	Plasma Group Meeting (organised by ALEX) Valerian Hall-Chen (ASTAR) --- Introduction to the ASTAR fusion programme		Valerian Hall-Chen (A*STAR) Yohei Kawazura (Utsunomiya U)
	Dmitri Uzdensky moves to Oxford as a new Professor of (Plasma) Physics.				Valerian Hall-Chen (A*STAR) Yohei Kawazura (Utsunomiya U)
	Tue 27 Aug	14:00 Freeman Rm	Plasma Seminar (organised by ALEX) Yohei Kawazura (Utsunomiya U) --- Rotational reduced MHD with curvature	JPP 88, 905880311 (2022) arXiv:2404.09252	Yohei Kawazura (Utsunomiya U)
	Nick Lopez leaves Oxford for a staff position with Tokamak Energy Ltd				Yohei Kawazura (Utsunomiya U)

Michaelmas Term of 2024