Title:

Diagnostic Tools for Heavy Ions in the Inner Corona and
the Modelling of their Heating and Acceleration


Xing Li
University of Wales



Abstract:

The study of the solar wind in the near Sun region is
important since no natural boundary exists between the corona
and the solar wind. In the absence of in situ measurements of
the solar wind, remote sensing techniques, such as
interplanetary scintillations measurements and spectroscopic
observations in the ultraviolet, offer valuable tools as
diagnostics for the plasma properties in the tenuous solar
wind near the Sun. SOHO observations indicate that minor ions
are preferentially heated and accelerated above coronal holes
and at streamer boundaries.  High frequency Alfvén waves and
ion cyclotron resonances are widely believed to be a primary
candidate for the observed heating and acceleration of the
different ion species. While fluid models incorporating these
processes have been successful in reproducing the enormous
energization of minor ions, wave/particle resonance is a rapid
process and the almost collisionless nature of the solar wind
renders the prediction of fluid models questionable. An
alternative approach is to use kinetic (semi-kinetic) and
hybrid models (where ions are treated as particles, and
electrons as a massless fluid) to investigate the energization
of the solar wind ions due to these waves. I will discuss the
successes and the limitations of these investigations, and the
implications of our recent hybrid simulations on the resonant
wave/particle interactions in the solar wind.