Ion Waves


Shear Driven Ion Waves in Plasmas

Objective: To measure experimentally the dispersion relation of ion-cyclotron, ion-acoustic, and diamagnetic-drift waves excited in WVUQ due to shear in parallel or perpendicular velocity, where “parallel” means “aligned with the magnetic field”

Significance: Gyroresonant waves in space plasma are responsible for the most common and most intense ion heating in the auroral plasma.

Long Range Goal: To establish experimentally the kinetic properties of low-frequency, finite-gyroradius, plasma instabilities in plasma having inhomogeneity parallel and perpendicular to the ambient magnetic field.

Collaborators: Mark Koepke, G. Ganguli (NRL) and former WVU graduate students V. Gavrishchaka, W. Amatucci, J. Carroll, and E. Reynolds.

Types of ion instabilities that have been experimentally investigated at WVU included the inhomogeneous energy density driven instability (IEDD), the shear-modified ion cyclotron instability (SMIC), the shear-modified ion acoustic instability (SMIA), and the shear-modified drift acoustic instability (SMDA).

These research experiments are done in the WVU Q-machine. Typical parameters are B=0.3 T, n= 1015 m-3, alkali-metal ions, Te = Ti = 0.2 eV.

These experimental results have been linked to theory. By doing so, we revealed numerous predictions in the model not described in the first theory publications.

Reference

1.  E.W. Reynolds, M E Koepke,J.J. Carroll, and S. Shinohara, Inhomogeneity scale lengths in a magnetized, low-temperature, collisionless, Q-machine plasma column containing perpendicular-velocity shear, 2006 Phys. Plasmas 13 092106

Copyright (2006) American Institute of Physics. This article may be downloaded for personal use only. Any other use requires prior permission of the author and the American Institute of Physics.

The listed article appeared in Physics of Plasmas and may also be found here.