%0 Journal Article
%T Study of high-beta supra-thermal plasma events in the vicinity of magneto-hydrodynamic shock-waves
%A P. K. Marhavilas
%A E. T. Sarris
%J Journal of Engineering Science and Technology Review
%D 2010
%I Kavala Institute of Technology
%X The ratio value ¨C known as plasma parameter ¡°beta¡± (¦Â) - of the interplanetary-plasma pressure (thermal pressure) to themagnetic field¡¯s (magnetic pressure) or of their energy densities, is critical for the space plasmas and has important consequencesto their properties. Although in the scientific literature the contribution of the supra-thermal particles to the plasmapressure is generally assumed negligible, we deduced, by analyzing energetic particles and magnetic field measurementsrecorded by the Ulysses spacecraft, that in a series of events, the energy density contained in the supra-thermal tail of theparticle distribution is comparable to or even higher than the energy density of the magnetic field, creating conditions ofhigh-beta plasma. In particular, in this paper we analyze Ulysses measurements of the energy density ratio (parameter ¦Âep) ofthe supra-thermal (20 keV to ~5 MeV) ions¡¯ (by the HI-SCALE instrument) to the magnetic field¡¯s (by the VHM/FGM instrument)in order to find occurrences of high-beta (¦Âep >1) supra-thermal plasma conditions in the vicinity of interplanetaryshock-waves. These high-beta ion events are associated with energetic particle intensity enhancements which have beenproduced by reacceleration at the shock fronts.
%K plasma parameter
%K ULYSSES data
%K magnetic shield
%K energy density
%K energetic particle
%U http://www.jestr.org/downloads/volume3/fulltext282010.pdf