Modeling of traveling compression regions in the Earth’s magnetotail by the spontaneous fast reconnection model

Abstract

The spontaneous fast reconnection model is applied to the traveling compression regions (TCRs) observed in the Earth’s magnetotail lobe region in association with substorms. For this purpose, virtual satellites are located at spatial points in the (low-β) magnetic field region in the three-dimenisonal simulation domain, so that each satellite directly observes the temporal variations of magnetic fields, obtained from simulations, in accordance with the growth and proceeding of the fast reconnection mechanism. If the virtual satellite is located ahead of the initial plasmoid formation, it observes a pulse-like field compression with the compression rate of more than 10% as well as the bipolar structure of the magnetic field component from northward to southward tilting, when the plasmoid center passes through the satellite location. On the other hand, if it is located behind the plasmoid formation, it observes the unipolar structure of the southward field component. The simulation results are shown to be, both quantitatively and qualitatively, in good agreement with the actual satellite observations. It is demonstrated that the TCR event is the fast reconnection mechanism itself that is seen in the ambient (low-β) magnetic field (magnetotail lobe) region.