Theory Department Weekly Seminar
Date/Time: March 18 (Thursday) 2010,10:45PM
Location: Theory Seminar Room (T169)

Title: Theory of the Dense Plasma Focus: Basic Model and Recent Developments

Speaker: Dr. Eric J. Lerner, Lawrenceville Plasma Physics, Inc.

There has been a revival in interest in the dense plasma focus, with
three large new machines coming on line in the past 18 months, and at
least two groups investigating the device’s possible use for pB11
fusion. This is due in part to a convergence by researchers on a basic
theoretical model that emphasizes the role of sub-millimeter dense
hot-spots or plasmoids. This seminar will discuss that basic model, the
evidence for it and its current state of development. In addition, we
will present recent theoretical developments: the use of an axial
magnetic field to maximize the energy transfer to the plasmoids and the
potential for the quantum magnetic field effect to reduce bremsstrahlung
emission from a pB11 plasma in the DPF.

Theory Department Weekly Seminar
Date/Time: February 4 (Thursday) 2010,10:45PM
Location: Theory Seminar Room (T169)

Title: Dual cascade in two dimensional gyrokinetic turbulence

Speaker: Dr.  Gabriel Plunk, University of Maryland

Abstract:

It is well known that two dimensional magnetized plasma turbulence (e.g. Hasegawa--Mima turbulence) can exhibit a dual cascade related closely to that found in two dimensional fluid turbulence: an "energy" quantity is transferred by nonlinear interactions to large scales while an "enstrophy" quantity is transferred to small scales.  Research during recent years has revealed a new type of dual cascade which is fundamentally kinetic.  That is, it operates via nonlinear phase mixing whereby sub-Larmor and sub-thermal scales are excited in the position and velocity space dependence of the gyrokinetic distribution function.

In this talk we will review the progress of research into this phase-space cascade, and touch upon recent advances.  Topics will include phenomenological scaling arguments, the Fjortoft argument for dual cascade, relationship to Hasegawa--Mima turbulence, a spectral theory of phase space and collisional entropy production.