First analyses of planar magnetic structures associated with the Halloween 2003 events from the Earth to Voyager 1 at 93 AU

Abstract

We perform the first analyses of planar magnetic structures beyond 5 AU. We also perform the first analyses of planar magnetic structures associated with the Halloween 2003 solar events. Our analyses show that planar magnetic structures (PMS) are associated with the interplanetary manifestation of the Halloween 2003 solar events over a wide range of heliocentric distances, heliolongitudes, and heliolatitudes. PMS are present at all five spacecraft (ACE, Ulysses, Cassini, Voyager 2, and Voyager 1); we investigate at distances ranging from the Earth to 93 AU. Our analyses indicate that generally the planes forming the PMS become better defined as they propagate farther out in the heliosphere. Also generally the cone angle of the PMS normal with respect to the radial direction decreases as the PMS propagate farther out in the heliosphere. This presence of PMS throughout the heliosphere is consistent with large-scale compressions associated with the interplanetary propagation of shocks and interaction regions and with possible consequences for cosmic ray and energetic particle modulation. In the case of Voyager 2, the PMS occur in the region after the main shock and are associated with enhanced interplanetary magnetic field magnitudes. This post shock region is associated with the modulation of galactic cosmic rays (>70 MeV/nuc). At Voyager 1 there is a "textbook example" of a PMS which also is associated with the modulation of galactic cosmic rays. It is tempting to associate these PMS with the "propagating diffusive barriers" of Wibberenz et al. (2002).