da Costa, Jr., Edio
Tsurutani, Bruce T.
Alves, Maria Virginia
Lakhina, Gurbax S.
Total Authors: 5
 IFMG, BR-35400000 Ouro Preto, MG - Brazil
 CALTECH, Jet Prop Lab, Pasadena, CA 91109 - USA
 INPE, BR-12227010 Sao Jose Dos Campos, SP - Brazil
 Indian Inst Geomagnetism, Navi Mumbai 410218 - India
Total Affiliations: 4
DEC 1 2013.
Web of Science Citations:
Magnetic field magnitude decreases (MDs) are observed in several regions of the interplanetary medium. In this paper, we characterize MDs observed by the Ulysses spacecraft instrumentation over the solar south pole by using magnetic field data to obtain the empirical size, magnetic field MD, and frequency of occurrence distribution functions. The interaction of energetic (100 keV to 2 MeV) protons with these MDs is investigated. Charged particle and MD interactions can be described by a geometrical model allowing the calculation of the guiding center shift after each interaction. Using the distribution functions for the MD characteristics, Monte Carlo simulations are used to obtain the cross-field diffusion coefficients as a function of particle kinetic energy. It is found that the protons under consideration cross-field diffuse at a rate of up to approximate to 11% of the Bohm rate. The same method used in this paper can be applied to other space regions where MDs are observed, once their local features are well known. (AU)