The Energetic Particle Populations of the Distant Heliosphere
In late 2003 as Voyager 1 moves beyond 90 AU in the recovery phase of solar cycle 23, the effects of the termination shock (TS) and the heliosheath on particle transport are becoming more evident. There are now detectable fluxes of 2.5 – 70 MeV electrons but at low intensity levels that suggest they are heavily modulated in the heliosheath. The modulation of galactic and anomalous cosmic rays is significant but much smaller than observed at 1 AU. At V1 a large increase of MeV ions was observed with a flat energy spectra which persisted over a period of 6.5 months. A second event has now been in progress for some eight months. These ions appear to originate at the TS. At V2, 17 AU behind V1, there are a series of 8 increases of low energy ions that occur approximately every 140 days starting in late 2000. Many of these increases can be related to specific periods of high solar activity that occurred some 6 months earlier.
Additional Information© 2004 American Institute of Physics. Issue Date: 15 September 2004.
Published - MCDaipcp04.pdf