BEGIN:VCALENDAR
VERSION:2.0
PRODID:Linklings LLC
BEGIN:VTIMEZONE
TZID:Europe/Stockholm
X-LIC-LOCATION:Europe/Stockholm
BEGIN:DAYLIGHT
TZOFFSETFROM:+0100
TZOFFSETTO:+0200
TZNAME:CEST
DTSTART:19700308T020000
RRULE:FREQ=YEARLY;BYMONTH=3;BYDAY=-1SU
END:DAYLIGHT
BEGIN:STANDARD
TZOFFSETFROM:+0200
TZOFFSETTO:+0100
TZNAME:CET
DTSTART:19701101T020000
RRULE:FREQ=YEARLY;BYMONTH=10;BYDAY=-1SU
END:STANDARD
END:VTIMEZONE
BEGIN:VEVENT
DTSTAMP:20210916T132450Z
LOCATION:Lise Girardin
DTSTART;TZID=Europe/Stockholm:20210706T150000
DTEND;TZID=Europe/Stockholm:20210706T153000
UID:submissions.pasc-conference.org_PASC21_sess133_msa109@linklings.com
SUMMARY:Nonlinear Multi-Species Collision Operator for Gyrokinetic Codes
DESCRIPTION:Minisymposium\n\nNonlinear Multi-Species Collision Operator fo
 r Gyrokinetic Codes\n\nDonnel, Villard, Brunner, Gheller, Murugappan\n\nTh
 e collisionality in tokamak plasmas is varying significantly across the pl
 asma radius. Indeed, the core of the plasma is in the low collisionality r
 egime and therefore requires a kinetic description. On the other hand, the
  edge and the scrape-off layer of the plasma are much more collisional due
  to the lower temperatures in these regions, and are therefore often descr
 ibed with a fluid approach. Furthermore, edge fluctuations are significant
 , making the linearization of the collision operator questionable. Edge-co
 re interactions are expected to play an important role for global confinem
 ent properties. But these interactions are difficult to study because of t
 he previously mentioned reasons. Global gyrokinetic codes with a nonlinear
  collision operator are the appropriate numerical tools to describe self-c
 onsistently the core and the edge of tokamak plasmas. In this context, a m
 ulti-species nonlinear collision operator has recently been derived and im
 plemented in the global gyrokinetic code ORB5. This operator relies on an 
 expansion of the distribution function in fluid moments to compute the Ros
 enbluth potentials. The operator is implemented using a Langevin approach 
 to solve the Fokker-Planck equation corresponding to the collisional evolu
 tion of the distribution function. This numerical approach results in a li
 ght computational cost of the collision operator and an easy parallelizati
 on. A noise control scheme compatible with collisions and conserving densi
 ty, momentum and energy have also been developped.The main steps of the de
 rivation of the collision operator and of its implementation as well as ph
 ysical tests will be described in details.\n\nDomain: Physics
END:VEVENT
END:VCALENDAR