Role of Small Scale Processes in Global Plasma Modelling

  1. Gordon R. Wilson
  1. G. Ganguli1,
  2. Y. C. Lee2 and
  3. P. J. Palmadesso2

Published Online: 18 MAR 2013

DOI: 10.1029/GM062p0017

Modeling Magnetospheric Plasma Processes

Modeling Magnetospheric Plasma Processes

How to Cite

Ganguli, G., Lee, Y. C. and Palmadesso, P. J. (1991) Role of Small Scale Processes in Global Plasma Modelling, in Modeling Magnetospheric Plasma Processes (ed G. R. Wilson), American Geophysical Union, Washington, D. C.. doi: 10.1029/GM062p0017

Author Information

  1. 1

    Space Plasma Physics Branch

  2. 2

    Special Project for Nonlinear Sciences, Plasma Physics Division, Naval Research Laboratory, Washington D.C. 20375

Publication History

  1. Published Online: 18 MAR 2013
  2. Published Print: 1 JAN 1991

ISBN Information

Print ISBN: 9780875900285

Online ISBN: 9781118663905



  • Space plasmas—Mathematical models—Congresses;
  • Magnetosphere—Mathematical models—Congresses


Waves in space plasmas are important not only because they act as a signature of local plasma conditions, and therefore have value as a diagnostic tool, but also because they can profoundly affect the macroscopic evolution of space plasmas by modifying transport properties (“anomalous transport”). Recent results from numerical simulations using generalized fluid codes [S. Ganguli and P.J. Palmadesso, J. Geophys. Res., 92, 8673, 1987], indicate that anomalous transport due to the current driven ion cyclotron instability plays an important role in the Magnetosphere-Ionosphere coupling process. In this regard, a new class of nonlocal instabilities sustained by shears in the ambient flows is of special interest since these instabilities can be excited at lower altitudes (unlike the current driven ion cyclotron instability) and can provide local heat sources. Hence, the velocity shear driven instabilities may be very important, especially to ion upflow processes such as the ‘ion cleft fountain'. Shears in the flow velocities, both parallel and perpendicular to the ambient magnetic field, are often encountered in space plasmas. The free energy residing in the velocity shears is capable of driving various instabilities and influencing others and thereby influencing macroscopic plasma behavior such as transport. Recent observations indicate significant correlations of turbulence with shears in the flow velocities. In this paper we develop a general nonlocal kinetic theory of electrostatic waves that can be excited in a magnetized warm plasma with nonuniform plasma flows along and across the ambient magnetic field, a typical scenario often encountered in magnetospheric and ionospheric plasmas. We discuss the various instabilities as limiting cases of the general theory and examine the interaction of shears in the flows parallel and perpendicular to the ambient magnetic field.