The Solar Wind Plasma
The solar wind is a large, magnetized, collisionless plasma, important for the geomagnetic activity that it drives at Earth and for its usefulness as a labora-tory for astrophysical processes. Like all other plasma experiments, the ex-perimental device must be characterized and understood to maximize its usefulness. In this talk we survey some time-series measurements obtained by spacecraft in the supersonic wind. The measurements show bumps and wiggles at all timescales. A difficulty in characterizing the solar wind from the time series measurements is discerning which bumps are “plasma struc-ture”, which bumps are “nonlinear Alfven waves”, which bumps are “turbu-lence”, and why are they there? The problem of determining the diffusivity and viscosity of a magnetized collisionless plasma is also addressed.
Joe Borovsky has been a Staff Member at Los Alamos National Lab. since 1982 and an Adjunct Research Scientist at the University of Michigan since 2011. He has been involved in theoretical, computational, and experimental physics. His theoretical research has included particle energization, plasma double layers, beam propagation, particle orbits, secondary-electron emission, and lightning. His experimental research has involved surface-interaction experiments using van de Graaff accelerators, linear accelerators, and scanning electron microscopes, has involved measuring auroral-arc thicknesses with telescopes, and has involved multidipole plasma devices. Current research interests focus on structure in the solar wind and the dynamics of the magnetosphere.