Study of Solar Energetic Particle Events with Ulysses, ACE Observations and Numerical Simulations

Abstract

We study the latitudinal extent of the near-relativistic electron events of 10 June 2000 and 26 December 2001, observed by both Ulysses and ACE. From the observations it is shown that the intensity of ACE was quite different from that of Ulysses. Through the numerical simulations, we obtain the SEPs time-intensity profiles, which generally fit well to the observations. To compare the observations we obtained the best fit parameters for the simulations. We suggest that the transport effects, especially the perpendicular diffusion effect, can cause the difference between the intensity profiles of ACE and Ulysses, which is dominated by particle transport at a large radial distance and high-latitude when a spacecraft has poor magnetic connection to the particle source. Furthermore, we present the particle source from the best fit parameters to show that the start and peak times of the particle sources are between the onset and max times of a flare in all the energy channels. Moreover, we propose models for the peak intensity and half width of the particle source, and the time interval from the flare onset to the particle source peak time. We show that the models generally agree with the best fit parameters.