IMPLICATIONS OF PROTON ANISOTROPY DEVELOPMENT OBSERVED BY THE ERNE INSTRUMENT DURING THE 9 JULY 1996 SOLAR PARTICLE EVENT

We analysed the solar particle event following the 9 July 1996 solar f lare. High-energy protons were detected by the ERNE instrument on boar d SOHO. Anisotropy of arriving protons revealed very peculiar non-mono tonic development. A short period of almost isotropic distribution was imbedded into the prolonged period of beam like distribution of 14-17 MeV protons. This implies the existence of a narrow magnetic channel with a much smaller mean free path than in the surrounding quiet solar wind plasma. We used Monte Carlo simulations of interplanetary transp ort to fit the observed anisotropies and intensity-time profiles. Prot on injection and transport parameters are estimated. The injection sce nario is found to be very close to the scenario of the 24 May 1990 eve nt, but the intensity and the different. The extreme anisotropy observ ed implies prolonged interplanetary transport parameters are different . The extreme anistropy observed implies prolonged injection of high-e nergy protons at the Sun and at the interplanetary shock front, and ei ther a very large mean free path (greater than or equal to 5 AU) outsi de the slow transport channel, or alternatively, a somewhat smaller me an free path (approximate to 2 AU) and enhanced focusing between the S un and the Earth.