02-09-2017, 03:59 PM
Arc strikes form the boundary between a magnetosphere and a magnetized environment environment. This occurs when the magnetic field of an astrophysical object interacts with surrounding ambient plasma. For example, when the solar wind, which flows with a relative velocity in the order of 400 km / s, meets the Earth's magnetic field, an arc form forms a boundary. For Earth and other magnetized planets, it is the boundary at which the velocity of stellar wind abruptly falls as a result of its approach to magnetopause. For stars, this boundary is typically the edge of the astrosphere, where the stellar wind meets the interstellar medium.
For several decades, the solar wind has been thought to form an arc collision at the edge of the heliosphere, where it collides with the surrounding interstellar medium. In moving away from the Sun, the point where the solar wind flow becomes subsonic is the ending shock, the point at which the balance between the interstellar medium and the solar wind is the heliopause, and the point where the flux of the interstellar medium becomes subsonic would be the arc of shock. It was thought that this solar arc collision was at a distance of about 230 AU from the Sun, more than double the distance of the termination shock encountered by the Voyager spacecraft. However, data obtained in 2012 from NASA's Interstellar Boundary Explorer (IBEX) indicate the absence of any solar arc collision. Together with the corroborating results of the Voyager spacecraft, these findings have motivated some theoretical refinements; the current thinking is that the formation of an arc collision is avoided, at least in the galactic region through which the Sun passes, by a combination of the strength of the local interstellar magnetic field and the relative velocity of the heliosphere.
For several decades, the solar wind has been thought to form an arc collision at the edge of the heliosphere, where it collides with the surrounding interstellar medium. In moving away from the Sun, the point where the solar wind flow becomes subsonic is the ending shock, the point at which the balance between the interstellar medium and the solar wind is the heliopause, and the point where the flux of the interstellar medium becomes subsonic would be the arc of shock. It was thought that this solar arc collision was at a distance of about 230 AU from the Sun, more than double the distance of the termination shock encountered by the Voyager spacecraft. However, data obtained in 2012 from NASA's Interstellar Boundary Explorer (IBEX) indicate the absence of any solar arc collision. Together with the corroborating results of the Voyager spacecraft, these findings have motivated some theoretical refinements; the current thinking is that the formation of an arc collision is avoided, at least in the galactic region through which the Sun passes, by a combination of the strength of the local interstellar magnetic field and the relative velocity of the heliosphere.