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Space Plasma Seminar: KAW Waves and the Dissipation of Magnetic Fluctuations in the Solar Wind

Charles Smith, University of New Hampshire

Monday, May 14, 2012, 4:00pm

Wilder 111

There is a growing recognition that MHD extensions of traditional hydrodynamic turbulence concepts can explain the evolution of the solar wind fluctuations. Recent efforts to use third-moment theory confirm that the rate of turbulent energy cascade closely matches the rate of in situ heating of solar wind protons. Some proponents of recent studies of small-scale fluctuations in the solar wind have proposed extreme viewpoints regarding the nature of solar wind turbulence and dissipation in the solar wind. One of those viewpoints holds that the small-scale inertial range fluctuations can be described as Kinetic Alfven Waves (KAWs) propagating nearly perpendicular to the mean magnetic field. They further argue that these waves are essentially non-dissipative at ion scales and that the inertial range extends to electron scales where electron Landau damping dissipates the waves and heats the plasma. I will present a series of analyses that challenge this view and suggest that the turbulent solar wind is a more interesting, more diverse, more dynamic object displaying many different processes, all of which combine to produce a more diverse turbulent system.