Authors: H. Kucharek, F. M. Ipavich, R. Kallenbach, B. Klecker, H. Gruenwaldt,
M. R. Aellig, P. Bochsler
Reference: 8 SOHO Workshop in Paris 1999
Abstract:
The solar wind provides the most comprehensive source of information
about solar isotopic abundance. The flow dynamic of the solar wind is
determined by the magnetic topology of the flux tubes. The slow solar
wind originating from closed field line regions, has a slow bulk
velocity and high freeze-in temperature, and the high speed solar wind
which has a low freeze-in temperature and originates from open flux
tubes in coronal holes. In situ solar wind measurements provide
therefore important informations on the present-day isotopic
composition of the outer convective zone of the Sun. Data from the
high resolution Mass Time-of-Flight spectrometer MTOF and the Charge
Time-Of-Flight spectrometer on board SOHO have been accumulated for
time periods in which coronal hole or non-coronal hole type plasma has
been detected in order to investigate the abundance ratios of
magnesium isotopes originating from these two different source regions
of the solar wind in the context of isotope fractionation.