Direction of the interstellar H atom inflow in the heliosphere: Role of the interstellar magnetic field

Abstract

Recently Lallement et al. (2005, Science, 307, 1447) reported that the direction of the flow of interstellar neutral hydrogen in the heliosphere is deflected by ~4° from the direction of the pristine local interstellar gas flow. The most probable physical phenomenon responsible for such a deviation is the interstellar magnetic field inclined to the direction of the interstellar gas flow. In this case the flow of the interstellar charged component is asymmetric and distorted in the region of the solar wind interaction with the local interstellar medium, which is called the heliospheric interface. The interstellar H atoms pass through the heliospheric interface and interact with the plasma component by charge exchange. Some imprints of the asymmetry of the heliospheric plasma interface should be seen in the distribution of the interstellar H atom component. In this letter we explore this scenario quantitatively and demonstrate that our new self-consistent 3D kinetic-MHD model of the solar wind interaction with the magnetized interstellar plasma is able to produce the measured deviation in the case of a rather strong interstellar magnetic field of ~2.5 μG inclined by ~45° to the direction of interstellar flow.