Propagation of Galactic Cosmic Rays and Jovian Electrons In The Heliosphere
Abstract
The propagation of energetic charged particles (ECPs) through the heliosphere has been a subject of study since the first observations of the solar cycle dependence of cosmic ray intensity and the discovery of solar energetic particles and their extended decay from the February, 1956 solar flare, which provided the first inklings of the existence of the heliosphere. In the years since, in-space observational studies have extended from near the orbit of Mercury to beyond the solar wind termination shock, and to high latitudes in the inner heliosphere. While the fundamental processes understood to describe the propagation have been basically unchanged since the work of Parker in the early 1960s, it has been observations that have for the most part driven our increasing insight into the mix of processes important for different particle types and energies in different regions of the heliosphere. By virtue of comprehensive on-line data archives, including the now developing Virtual Observatories, relevant in-space observations exist in readily accessible form from the 1970s up to the present, covering energy ranges from fractions of an MeV up through several GeV. Of the ECP populations that pervade the heliosphere, galactic cosmic rays and Jovian electrons represent two poles. By virtue of their high magnetic rigidities and consequent large gyro-radii, galactic cosmic rays are sensitive primarily to large-scale structure in the heliosphere. On the other hand, Jovian electrons, though they have the high velocities necessary to provide mobility for propagation throughout the heliosphere, their rigidities of only a few MV and consequent small gyro-radii make them sensitive both to the large scale topology of the interplanetary magnetic field and to small scale structure on the scale of hundredths of an AU. In this talk I will focus on observations of these two particle populations over the most recent solar cycles to identify and discuss the influence of both large-and small-scale structure on propagation of ECPs in the heliosphere.
- Publication:
-
38th COSPAR Scientific Assembly
- Pub Date:
- 2010
- Bibcode:
- 2010cosp...38.1649M