HR: 16:55h
AN: SH22C-04    [PDF]
TI: Interstellar Magnetic Field and its Influence on the Heliospheric Interface.
AU: * Pogorelov, N V
EM: nikolaip@citrus.ucr.edu
AF: Institute of Geophysics and Planetary Physics, Univeristy of California, Riverside, 900 University Avenue, Riverside, CA 92521 United States
AU: * Pogorelov, N V
EM: nikolaip@citrus.ucr.edu
AF: Institute for Problems in Mechanics, Russian Academy of Sciences, 101-1 Vernadskii Avenue, Moscow, 119526 Russian Federation
AU: Florinski, V
EM: vflorins@citrus.ucr.edu
AF: Institute of Geophysics and Planetary Physics, Univeristy of California, Riverside, 900 University Avenue, Riverside, CA 92521 United States
AU: Zank, G P
EM: zank@ucrac1.ucr.edu
AF: Institute of Geophysics and Planetary Physics, Univeristy of California, Riverside, 900 University Avenue, Riverside, CA 92521 United States
AB: The strength and direction of the interstellar magnetic field (ISMF) in the Local Interstellar Cloud (LIC) have not been directly measured and remain the less known parameters affecting the interaction of the solar wind (SW) with the local interstellar medium (LISM). The values as small as $\sim 1.5\, \mu\mathrm{G}$ are consistent with the observations of the pulsar dispersion and rotation measures, whereas the estimates of the heliospheric confinement pressure yield the upper limit of $\mathbf{B}_\infty \sim 3-4\, \mu\mathrm{G}$. The latter values are derived assuming that ISMF is directed perpendicular to the LISM velocity vector $\mathbf{V}_\infty$ with respect to the Sun. We analyze the consequences of the SW encounter with LISM possessing magnetic fields in a wide range of strengths and directions. Both axisymmetric ($\mathbf{B}_\infty\parallel \mathbf{V}_\infty$) and 3D configurations are considered. It is shown that the topology of the bow shock strongly depends on its being fast or slow. Special attention is given to slow bow shocks in the quasi-field-aligned cases, where their existence is stipulated by charge exchange processes in the upstream region. The comparison of theoretical results predicted in this case by our model with the Hubble Space Telescope measurements showed very good agreement. Thus, stronger magnetic fields, which are necessary to satisfy the general equilibrium between the Local Bubble and LIC gases, cannot be excluded from consideration. Fields of such strengths are involved in the model of the LIC origin due to Cox \& Helenius (2003). We also analyze various superfast cases, including those where fast parallel shocks cannot exist, while switch-on shocks should be excluded in the presence of certain symmetry restrictions. This usually results in the appearance of additional discontinuities between the bow shock and the heliopause. We show that this scenario is not necessarily valid if the interplanetary magnetic field is taken into account. In this case the ISMF lines exhibit complex three-dimensional topology, which may influence the general picture of the cosmic ray diffusion into the heliosphere. Regimes are also investigated, where $\mathbf{B}_\infty$ is nearly perpendicular to \mathbf{V}_\infty$. They are accompanied by the reconnection of the interplanetary and interstellar magnetic field lines and reveal stronger dependence on the ISMF strength than in field-aligned cases.
DE: 2124 Heliopause and solar wind termination
DE: 2144 Interstellar gas
SC: SPA - Solar and Heliospheric Physics [SH]
MN: 2003 Fall Meeting