Extensions of the Fisk & Gloeckler Model for the Nose Region of the Heliosheath

Abstract:

Fisk and Gloeckler (ApJ 789, 41, 2014) developed a detailed model for the nose region of the heliosheath, hereinafter referred to as the F&G model, which is able to account for many of the significant Voyager and IBEX observations; in particular: (1) the plasma densities observed by Gurnett et al. (2013) from Voyager 1 (V1) that resemble the densities expected in the interstellar medium; (2) the direction of the magnetic field, which does not change at the heliocliff, where the ACRs escape; (3) the full IBEX ENH spectra observed in the directions of V1 and Voyager 2 (V2), particularly the low-energy ENH measurements, for which no other explanation is available; (4) the magnetic field strength observed by V1 in a region where the components of the solar wind velocity normal to the magnetic field become very small; (5) the escape of ACRs and the entry of GCRs beyond the heliocliff. The F&G model thus provides a context in which to interpret current and future Voyager observations, such as the lack of turbulence in the region currently being explored by V1, or the source of the IBEX ribbon. These and other extensions of the F&G model will be discussed.