Diffusive-Shock-Accelerated Interplanetary Ions At Several Energies During the Solar Cycle 21 Maximum     

Rodríguez-Pacheco  J.  Sequeiros  J.  Del Peral  L.  Bronchalo  E.  Cid  C. 《Solar physics》1998,181(1):185-200

The most intense energetic particle (mainly proton) events in the energy range 36–1600 keV, during the years of maximum activity of solar cycle 21 (1978 to 1982), have been studied with regard to their spectra, temporal profiles, source location at the Sun, interplanetary plasma parameters and interplanetary magnetic field topology. In all the events, the particles were accelerated by the 'Diffusive Shock' acceleration mechanism, because all the events were 'long-duration events', shock-associated, and their spectra fitted to a power-law energetic particle spectrum dJ/dE E^-\gamma with the exponent values ranging from 1.25 up to 1.94, with a mean value of 1.60 ± 0.06. We also show that the spectral indexes are related to the shock properties by a linear expression. The solar sources were located on a wide longitudinal belt extending from 50^ W up to 73^ E. Neither the spectral indexes nor the shock parameters present any dependence on the source location at the Sun. Finally, only one event showed the complete set of properties that characterize the presence of a magnetic cloud associated with the event.  相似文献   

Evidence of Magnetic Flux Ropes in the Solar Wind From Sigmoidal and non-Sigmoidal Active Regions     

C. Cid  M.A. Hidalgo  J. Sequeiros  J. Rodríguez-pacheco  E. Bronchalo 《Solar physics》2001,198(1):169-177

We have examined WIND magnetic field and plasma data during the first half of 1998 in order to find encounters of this spacecraft with magnetic clouds. From the events obtained through this search, we have selected four of them taking into account their solar origin. The four magnetic clouds are related to halo or partial halo CMEs, but the morphology of the active region before the eruption is sigmoidal for three of them and non-sigmoidal for the other one. We have analyzed these events in the solar wind by fitting the experimental data to a non-force-free flux-rope model. We conclude that both kinds of active regions develop in the solar wind an ejection with a flux-rope topology.  相似文献