University of Maryland
Atlantic Building, Room 2400
4:30 PM Thursday, October 3, 2013
Coffee, Tea & Snacks 4:15-4:30 PM

Tim Felten
Ruhr-Universität Bochum
Spontaneously Emitted Fluctuations in Unmagnetized Plasmas

Every stable plasma spontaneously emits electromagnetic fluctuations due to the random motions of the charged plasma particles. Consequently, the plasma variables such as density, pressure, and electromagnetic fields fluctuate in position and time. We will derive the general expressions for the electromagnetic fluctuation spectra in unmagnetized plasmas using fully relativistic dispersion functions and form factors for the important class of isotropic plasma particle distribution functions. The special case of aperiodic fluctuations will be analyzed for an electron-proton plasma with a Maxwellian and a Lorentzian distribution function.
The fluctuation intensities are dominated by the contribution from a new collective, damped mode. We will determine the magnetic field strengths from this mechanism.

Sponsored by: Department of Physics and the Institute for Physical Science and Technology, University of Maryland. For information call Victoria at (301) 405-4811 or go to the UMD Space Physics group seminar web site.

There is free parking after 4:00 PM in lot B (the big parking garage across the street from the ATL building). There are a limited number of spaces in lot Q next to the new ATL wing with free parking after 4PM even when there is a basketball game on campus.