"Magnetic Ropes" by Walter Gekelman (UCLA)

Date: 
Thursday, February 4, 2016 - 4:00pm to 5:00pm
Series: 
Physics and Astronomy Colloquium

Thursdays, 4:00-5:00 pm

1-434 Physics and Astronomy (map)
Reception from 3:30-4:00 p.m.
(unless otherwise posted)

Guest Speaker: Walter Gekelman (University of California, Los Angeles)

Talk Title:  "Magnetic Ropes"

Abstract:

Magnetic Ropes or flux ropes litter the surface of the sun, and presumably all stars.  They come in all sizes, from a mere 10,000 miles in length to giants that can reach all the way to earth. The magnetic field of the ropes forms layers of helices with pitch increasing with radius.  The associated current is helical as well.  Flux ropes can be repeatedly formed and studied in great detail in the Large Plasma Device (LAPD) in UCLA.  The magnetic field of the ropes, their associated currents, electric fields, flows, density, temperature and motion have been studied in great detail throughout the plasma volume and at thousands of times. In this talk we will discuss what happens when single or multiple ropes are present.  A single rope twists about itself like a wrapped up towel and under the right condition can kink and flail about.  Two ropes twist about themselves and each other in space and time and if they collide some of their magnetic field can be destroyed. The magnetic energy then goes into other forms such as heat, flows and various plasma waves. Flux rope collisions may explain, in part, the heating of the solar corona, which is 200 times hotter than the surface of the sun. In a rope collision magnetic field lines, which closely followed one another before the crash can rapidly diverge in space afterwards.  In certain conditions the ropes become chaotic.  The 3D magnetic fields, currents, fields and flows form beautiful patterns many of which will be shown. 

For more information, contact Jay Hauser

We thank the following people for their contributions to the wine fund for the post-colloquium reception:
Prof. Dolores Bozovic, Prof. Mike Cornwall, Prof. Bob Cousins, Prof. Andrea Ghez, Prof. Karoly Holczer, Prof. Eric Hudson, Robert Huff, Prof. Alex Kusenko, Prof. Myank Mehta, Prof. John Miao, Prof. Roberto Peccei, Prof. Claudio Pellegrini, Prof. David Saltzberg, Prof. Jean Turner and Prof. Ben Zuckerman.

Event Attachments: 
Location: 
1-434 PAB