We have used a large number of magnetopause crossings by the Magnetospheric Multiscale (MMS) mission to investigate macroscopic properties of this current sheet, with emphasis on the flanks of the magnetopause. Macroscopic features such as thickness, location, and motion of the magnetopause were calculated as a function of local time sector. The results show that the flanks of the magnetopause are significantly thicker than the dayside magnetopause. Thicknesses vary from about 650 km near noon to over 1,000 km near the terminator. Current densities vary in a similar manner, with average current densities around noon almost twice as high as near the terminator. We also find a dawn-dusk asymmetry in many of the macroscopic parameters; the dawn magnetopause is thicker than at dusk, while the dusk flank is more dynamic, with a higher average normal velocity.
Global Pi2 pulsations have mainly been associated with either low/middle latitudes or middle/ high latitudes and, as a result, have been treated as two different types of Pi2 pulsations, either the plasmaspheric cavity resonance or the transient response of the substorm current wedge, respectively. However, in some reports, global Pi2 pulsations have a single period spanning low/middle/high latitudes. This "super" global type has not yet been satisfactorily explained. In particular, it has been a major challenge to identify the coupling between the source region and the ground. Here we report two consecutive super global Pi2 events which were observed over a wide latitudinal and longitudinal range. Using four spacecraft that were azimuthally spread out in the nightside and one spacecraft in the tail lobe, it was possible to follow the Pi2 signal along various paths with time delays from the magnetotail to the ground. Furthermore, it was found that the global pulsations were a combination of various modes including the transient Alfvén and fast modes, field line resonance, and possibly a forced cavity-type resonance. As for the source of the Pi2 periodicity, oscillatory plasma flow inside the plasma sheet during flow braking (e.g., interchange oscillations) is a likely candidate. Such flow modulations, resembling the ground Pi2 pulsations, were recorded for both events.
Emergency officers could often benefit from a route planning system that is based on constant traffic monitoring and complex decision making, seeking to give victims another breath of hope by assisting emergency units with reaching them on time. The main challenge is providing responses in a continuously evolving environment within a prescribed time frame, while using limited resources and information that is often incomplete or uncertain. This paper presents a route control concept for emergency vehicles through urban traffic. The proposed genetic controller is designed to dynamically reassess the route while the vehicle passes through the road network, continuously generating new routes based on current traffic. The algorithm is tested in an agent based simulation model that includes both traffic participants and a distributed traffic control system.
We propose a scenario that filamentary structure appears together with propagating waves on the scale of ion gyroradius. The method is based on two-dimensional ion particle-in-cell (or hybrid) simulation in low-beta plasmas. Coherent, filamentary structures in space plasmas are found as the zero-frequency mode in the wavenumber-frequency domain. The existence of the wave modes might be the key to understand filament formation in space plasmas.
At 10:00 UT on 25 February 2008, Cluster 1 spacecraft crossed the near‐midnight auroral zone, at about 2 RE altitude, while two of the Time History of Events and Macroscale Interactions During Substorms (THEMIS) spacecraft, THD and THE, observed multiple flow bursts on the near‐conjugate plasma sheet field lines. The flow shear pattern at THEMIS was consistent with the vortical motion at duskside of a localized flow channel. Coinciding in time with the flow bursts, Cluster 1 observed bursts of counterstreaming electrons with mostly low energies (≤441 eV), accompanied by short time scale (<5 s) magnetic field disturbances embedded in flow‐associated field‐aligned current systems. This conjugate event not only confirms the idea that the plasma sheet flows are the driver of the kinetic Alfvén waves accelerating the low‐energy electrons but is a unique observation of disturbances in the high‐altitude auroral region relevant to the multiple plasma sheet flows.
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