OXFORD PLASMA THEORY GROUP

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" 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, Felix Parra 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;

  Hilary Term of 2019

The seminars/group meetings will be on Thursday at 11:00 in 501 Denys Wilkinson Building, except where indicated otherwise below.
Note also the ALP Seminars (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

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
It is better to be roughly right than precisely wrong. Maynard Keynes 

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
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
There are many big Buts here... I like big Buts. Matt Kunz
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 and 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 and Steve Balbus
Это качественное объяснение недостаточно качественное. 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
[these quotes are mostly from Oxford plasma seminars and Vienna meetings]

Wk Date
Time
& place
Speaker & Topic
Background reading
Comings and goings
(incl. visitors in town)

Thu
Jan 3
No seminar (Happy New Year!)

0
Thu
Jan 10
No seminar

I
Thu
Jan 17
11:00
501
DWB
Plasma Seminar (organised by FELIX)
Albert Mollen (IPP Greifswald) --- Impurity transport in stellarator plasmas
PPCF 60, 084001 (2018)
PRL 118, 155002 (2017)
Albert Mollen
(IPP Greifswald)
II
Thu
Jan 24
11:00
501
DWB
Plasma Seminar (organised by ALEX & ARCHIE)
Jack Hare (Imperial) --- Magnetic reconnection, instabilities and turbulence in pulsed-power driven plasmas
PRL 118, 085001 (2017)
PoP 24, 102703 (2017)
Jack Hare
(Imperial)
III
Thu
Jan 31
11:00
501
DWB
Plasma Seminar (organised by ALEX) 
Denis St-Onge (Princeton) --- Turbulent dynamo in a collisionless magnetized plasma
The Universe is magnetized. While magnetic-field strengths of just ~10^{-18} G are required to achieve this both in our Galaxy and in clusters of galaxies, observations of Faraday rotation, Zeeman splitting, and synchrotron emission all make the case of ubiquitous ~μG fields. That these systems are not content with hosting weaker fields is surprising, at least until one realizes that the energy density of a ~μG field is comparable to that of the observed turbulent motions. It is then natural to attribute the amplification and sustenance of (at least the random component of) the interstellar and intracluster magnetic fields to the fluctuation (or “turbulent”) dynamo. In this talk, we will explore the various ways in which plasma microphysics makes magnetic-field amplification in weakly collisional plasmas by macroscale turbulent motions possible, with application to the intracluster medium of galaxy clusters.
ApJ 863, L25 (2018)
Matt Kunz,
Denis St-Onge
(Princeton)

IV
Thu
Feb 7
11:00
501
DWB
Plasma Group Meeting (organised by ALEX)
Free discussion
[if that fails, Alex Schekochihin --- Nonlinear MHD dynamo and reconnection revisited]


V
Thu
Feb 14
11:00
501
DWB
Plasma Group Meeting (organised by ALEX)
Catherine Felce (Merton) --- A toy 2D model for multi-scale electron and ion plasma turbulence
This is based on a summer research project at Princeton with Greg Hammett and Noah Mandell.

project
report
on request

VI
Thu
Feb 21
11:00
501
DWB
Plasma Seminar (organised by ALEX)
Archie Bott --- Investigating turbulent amplification of magnetic fields with laser-plasma experiments
DPhil
thesis
from
on author
on request
Roger Blandford
(Stanford)
Fri
Feb 22
14:00
D Sciama
LT
Theoretical Physics Colloquium:
Roger Blandford (Stanford) --- Extreme astrophysics
The electromagnetic spectrum has been opened up from meter radio waves to 100 TeV photons and augmented with 10 - 300 Hz gravitational wave, MeV - PeV neutrinos and MeV - ZeV (160 Joule) cosmic ray messages. Consequently, there is a high rate of discovery and understanding of phenomena whose explanation invokes accepted physics - classical (including general relativity), atomic, nuclear and particle (including QED) processes - in extreme environments. The richness of the discovery space can be epitomized by describing some new observations and ideas pertaining to relativistic jets formed by massive spinning black holes, Ultra High Energy Cosmic Rays accelerated by strong shock waves surrounding rich clusters of galaxies and Fast Radio Bursts, generated by neutron stars with 100 GT magnetic fields.
NOTE: Roger is also giving an Occam Lecture at Merton, "Confirmation, Conviction and Cosmology", on Monday 25 February.
VII
Thu
Feb 28
11:00
501
DWB
Plasma Group Meeting (organised by FELIX)
Alessandro Geraldini (Maryland) --- Making stellarator surfaces great again

Roger Blandford
(Stanford)
Alessandro Geraldini
(Maryland)
Fri
Mar 1
14:00
D Sciama
LT
Special Astro/Plasma Seminar:
Payel Das (Oxford) --- The nearby Universe: our window into gigayears of galaxy evolution
VIII
Thu
Mar 7
11:00
501
DWB
Plasma Seminar (organised by MICHAEL & YOHEI)
Makoto Sasaki (Kyushu U, Japan) --- Spatio-temporal dynamics of turbulence trapped in geodesic acoustic modes
Prediction of the spatial profile of tubulence is an important subject in studies of magnetically confined plasmas. The spatial profile of turbulence is determined not only by the local gradient of the density and temperature, but also by the nonlocal processes such as the interaction of the flow shear and the turbulence spreading. In this seminar, a novel role of the sheared flow on the turbulence is presented. The trapping of the turbulence by the flow is shown to be important for determining their spatial propagation and profile, and this effect is comparable to that by the turbulence spreading.
Sci. Rep. 7, 16767 (2017)
PoP 25, 012316 (2018)
Makoto Sasaki
(Kyushu U, Japan)
14:00
D Sciama
LT
Special Astro/Plasma Seminar:
Ralph Schoenrich (Oxford) ---Exploring the Milky Way with Gaia

9
Thu
Mar 14
11:00
501
DWB
Plasma Seminar (organised by MICHAEL & NICOLAS)
Quentin Wargnier (Ecole Polytechnique) --- Mathematical modeling and high fidelity adaptive simulations of astrophysical plasmas with accurate transport: application to a partially ionized plasma under solar chromospheric conditions
This contribution deals with the fluid modeling of multicomponent magnetized plasmas in thermo-chemical non-equilibrium from the partially- to fully-ionized collisional regimes, aiming at simulating magnetic reconnection in Sun chromosphere conditions. Such fluid models are required for large-scale simulations by relying on high performance computing. The fluid model is derived from a kinetic theory approach, yielding a rigorous description of the dissipative and non-equilibrium effects and a well-identified mathematical structure. We  start from a general system of equations that is obtained by means of a multiscale Chapman-Enskog method, based on a non-dimensional analysis accounting for the mass disparity between the electrons and heavy particles, including the influence of the electromagnetic field and transport properties. The latter are computed by using a spectral Galerkin method based on a converged Laguerre-Sonine polynomial approximation. Then, in the limit of small Debye length with respect to the characteristic scale in the solar chromosphere, we derive  a two-temperature single-momentum multicomponent diffusion model coupled to Maxwell's equations, which is able to describe fully- and partially-ionized plasmas, valid for the whole range of solar chromosphere conditions. The second contribution is the development and verification of an accurate and robust numerical strategy based on a massively parallel code with adaptive mesh refinement capability. We rely on the canop code, based on two libraries: P4EST for the adaptive mesh refinement (AMR) capability and MUTATION++ for computing the transport properties with a high level of accuracy, in order to ensure that the full spectrum of scales and the dynamics of the magnetic reconnection process are captured. Finally, we present a 2D and 3D magnetic reconnection configuration in solar chromospheric conditions and assess the potential of the numerical strategy for simulating astrophysical plasmas.

Marc Massot,
Quentin Wargnier
(Ecole
Polytechnique)
10
Thu
Mar 21
11:00
501
DWB
Plasma Journal Club (organised by DAVID)
Paper to be discussed: Rotating MHD turbulence by Bell and Nazarenko

Some additional/background reading (suggested by Alex):
MHD turbulence: review
Rotating turbulence: a view; another view; experiment (and references therein)


Thu
Mar 28
11:00
501
DWB
Plasma Group Meeting (organised by FELIX)
Jason Parisi --- Toroidal and slab ETG dominance in JET pedestals
preprint
from
author
on request


31 Mar - 5 Apr
Univ
International Conference on High-Energy-Density Science
Henrik Latter
(Cambridge)
Thu
Apr 4
11:00
Paton Rm
Beecroft
Plasma Seminar (organised by ALEX)
Henrik Latter (Cambridge) --- TBC


Thu
Apr 11.
11:00
501
DWB
Plasma Group Meeting (organised by MICHAEL)
TBA



15-17 Apr
Sherwood Meeting in Princeton

Thu
Apr 18.
No seminar
0
Thu
Apr 25
11:00
501
DWB
Plasma Journal Club (organised by JASON)
Paper to be discussed: TBA


I
Thu
May 2
11:00
501
DWB
Plasma Seminar (organised by ALEX)
Ilya Dodin (Princeton) --- TBA

Ilya Dodin
(Princeton)
Thu
May 3
14:00
D Sciama
LT
Theoretical Physics Colloquium:
Ilya Dodin (Princeton) --- TBA
II
Tue
May 7
16:00
D Sciama
LT
Special Astro/Plasma Seminar:
Mattia Sormani (ITA Heidelberg) --- Understanding the gas dynamics in the central 3 kpc of the Milky Way

Bence Kocsis
(Eotvos Lorand U,
Budapest)
Mattia Sormani
(ITA Heidelberg)
Thu
May 9
11:00
501
DWB
Plasma Group Meeting (organised by FELIX)
TBA

14:00
D Sciama
LT
Special Astro/Plasma Seminar:
Bence Kocsis (Eotvos U, Budapest) --- TBA

III
Thu
May 16.
11:00
501
DWB
Plasma Group Meeting (organised by MICHAEL)
TBA


IV

Mon
May 20
11:30
D Sciama
LT
Special Astro/Plasma Seminar:
Jason Sanders (IoA Cambridge) --- TBA

J-B Fouvry
(IAS Princeton)
Jason Sanders
(IoA Cambridge)
Jono Squire
(Otago)
Thu
May 23
11:00
D Sciama
LT
Plasma Seminar & Special Astro/Plasma Seminar:
Jean-Baptiste Fouvry (IAS Princeton) --- TBA

V

Tue
May 28
11:00
D Sciama
LT
Special Astro/Plasma Seminar:
Jono Squire (Otago) --- TBA

Jono Squire
(Otago)
Thu
May 30.
11:00
501
DWB
Plasma Group Meeting (organised by FELIX)
TBA

VI
Thu
June 6.
11:00
501
DWB
Plasma Group Meeting (organised by MICHAEL)
TBA


VII
Thu
June 13
11:00
501
DWB
Plasma Group Meeting (organised by ALEX)
TBA


VIII
Thu
June 20
11:00
501
DWB
Plasma Group Meeting (organised by MICHAEL)
TBA

Bill Dorland
(Maryland)
9
Thu
June 27
11:00
501
DWB
Plasma Group Meeting (organised by ALEX)
TBA

Bill Dorland
(Maryland)
10
Thu
July 4.
11:00
501
DWB
Plasma Group Meeting (organised by FELIX)
TBA

Bill Dorland
(Maryland)

Thu
July 11
11:00
501
DWB
Plasma Group Meeting (organised by ALEX)
TBA

Bill Dorland
(Maryland)

Thu
July 18
11:00
501
DWB
Plasma Group Meeting (organised by FELIX)
TBA

Bill Dorland
(Maryland)

Thu
July 25
11:00
501
DWB
Plasma Group Meeting (organised by MICHAEL)
TBA