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SUMMARY:Experiments on Magnetic Flux Ropes - Walter Gekelman (UCLA)
DTSTART:20251028T160000Z
DTEND:20251028T170000Z
UID:TALK237718@talks.cam.ac.uk
CONTACT:David Hosking
DESCRIPTION:Magnetic Flux Ropes are comprised of twisted magnetic fields a
 nd currents. The pitch of the field varies with radius of the ropes. Photo
 graphs of X ray emission from the solar corona suggest the surface of the 
 sun is littered with them. Some are arched and others expand outwards to b
 ecome coronal mass ejections. Under the right conditions they become kink 
 unstable. If two or more are close to one other the kink instability can c
 ause them to collide and trigger magnetic field line reconnection. Flux ro
 pes have been produced in the Large Plasma Device at UCLA and studied for 
 over a decade. This talk will review some major results. The Quasi Seperat
 rix layer (QSL) \, a three dimensional region in which reconnection occurs
 \, has been measured. Volumetric measurements of inductive and space charg
 e electric fields\, plasma density\, magnetic field\, ion flow\, electron 
 temperature and rope current were undertaken at over 42\,000 spatial locat
 ions and thousands of time steps. These were used to calculate the reconne
 ction rate\, canonical helicity\, and all the terms\, save resistivity\, i
 n Ohms law. Ohms law was found to be non-local. The rope magnetic fields w
 ere determined to be deterministically chaotic. Finally measured topologic
 al quantities such as twist and winding number were used to determine wher
 e in the QSL magnetic reconnection occurred.
LOCATION:MR14 DAMTP and online
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