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VERSION:2.0
CALSCALE:GREGORIAN
PRODID:UW-Madison-Physics-Events
BEGIN:VEVENT
SEQUENCE:4
UID:UW-Physics-Event-4671
DTSTART:20171113T180000Z
DTEND:20171113T190000Z
DTSTAMP:20260419T004139Z
LAST-MODIFIED:20171101T220102Z
LOCATION:Chamberlin 2241
SUMMARY:Schnack Memorial Seminar: Nonlinear Modeling of Mode Locked St
 ates Induced by Transient Magnetic Perturbations\, Plasma Physics (Phy
 sics/ECE/NE 922) Seminar\, Dr. Matthew Beidler\, Department of Enginee
 ring Physics\, UW Madison
DESCRIPTION:Externally applied 3D magnetic fields in tokamaks can pene
 trate into the plasma and lead to forced magnetic reconnection\, and h
 ence magnetic islands\, on resonant surfaces. Analytic theory has been
  reasonably successful in describing many aspects of this paradigm wit
 h regard to describing the time asymptotic-steady state [1]. However\,
  understanding the nonlinear evolution into a low-slip\, field-penetra
 ted state\, especially how MHD events such as sawteeth and ELMs precip
 itate this transition\, is in its early development. We present nonlin
 ear computations employing the extended-MHD code NIMROD\, building on 
 previous work [2] by incorporating a temporally varying external pertu
 rbation as a simple model for an MHD event that produces resonant magn
 etic signals. A parametric series of proof-of-principle computations a
 nd accompanying analytical theory characterize the transition into a m
 ode-locked state with an emphasis on detailing the temporal evolution 
 properties.<br>
\n<br>
\n[1] R. Fitzpatrick\, Nucl. Fusion 33\, 1049 (
 1993)<br>
\n[2] M.T. Beidler\, J.D. Callen\, C.C. Hegna\, and C.R. Sov
 inec\, Phys. Plasmas 24\, 052508 (2017)
URL:https://www.physics.wisc.edu/events/?id=4671
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