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VERSION:2.0
CALSCALE:GREGORIAN
PRODID:UW-Madison-Physics-Events
BEGIN:VEVENT
SEQUENCE:5
UID:UW-Physics-Event-8450
DTSTART:20231016T170000Z
DTEND:20231016T181500Z
DTSTAMP:20260414T012209Z
LAST-MODIFIED:20231006T183403Z
LOCATION:1610 Engineering
SUMMARY:Fluid Modeling of Runaway Electron Beams\, Plasma Physics (Phy
 sics/ECE/NE 922) Seminar\, Alex Sainterme\, UW-Madison
DESCRIPTION:A now-common approach for modeling runaway electron (RE) e
 ffects on<br>
\nmacroscopic tokamak plasma dynamics introduces a simpl
 e fluid<br>
\ndescription of a separate beam-like electron species tra
 veling parallel to<br>
\nmagnetic field lines in a resistive MHD backg
 round plasma [Bandaru\, et<br>
\nal.\, PRE 99\, 063317(2019)]. The RE 
 beam provides a source of<br>
\nresistance-free current density whose 
 direction depends on the timeevolving<br>
\nmagnetic field. Sources of
  runaway electron density are<br>
\nincluded to approximate the accele
 ration of electrons to high energies in<br>
\nthe presence of strong p
 arallel electric fields. This fluid RE model has<br>
\nbeen implemente
 d in the non-ideal MHD code NIMROD. Some initial<br>
\ncalculations ar
 e shown to benchmark the implementation of the RE<br>
\nsource model. 
 The model has also been used to study linear stability of a<br>
\npart
 icular MHD equilibrium supported entirely by RE current. It is<br>
\nf
 ound that in addition to modifying the growth of the tearing mode\, th
 e<br>
\nRE beam is itself unstable to a form of ’resistive hose’ i
 nstability<br>
\n[Rosenbluth\, Phys. Fluids 3\, 932(1960)]. Scaling of
  the growth rate with<br>
\nthe resistivity of the bulk plasma shows t
 hat for Lundquist number less<br>
\nthan 10<sup>4</sup>\, the resistiv
 e  hose is the fastest growing linear<br>
\ninstability in the system.
  This is relevant for RE beams generated in<br>
\ntokamak disruptions 
 where the background plasma is cold and resistive.<br>
\nPreliminary n
 onlinear simulations of the hose mode are presented.<br>
\n<br>
\nBio:
 <br>
\nAlex Sainterme is a fifth year PhD student in the Nuclear Engin
 eering<br>
\nand Engineering Physics department working under Professo
 r Carl Sovinec.<br>
\nAlex’s research focuses focuses on simulation 
 and modeling of runaway<br>
\nelectron dynamics and disruptions in tok
 amaks.
URL:https://www.physics.wisc.edu/events/?id=8450
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