Geoeffective jets impacting the magnetopause are very common.

摘要: The subsolar magnetosheath is penetrated by transient enhancements in dynamic pressure. These enhancements, also called high-speed jets, can propagate to the magnetopause, causing large-amplitude yet localized boundary indentations on impact. Possible downstream consequences of these impacts are, e.g., local magnetopause reconnection, impulsive penetration plasma into magnetosphere, inner magnetospheric and surface waves, drop outs other variations radiation belt electron populations, ionospheric flow magnetic field observed ground. Consequently, jets be geoeffective. extend their geoeffectiveness influenced amount mass, momentum, energy they transport, i.e., how large are. Their overall importance framework solar wind-magnetosphere coupling determined often geoeffective size hit dayside magnetopause. In this paper, we calculate such jet impact rates for first time. From a data set Time History Events Macroscale Interactions during Substorms (THEMIS) multispacecraft observations, find distributions scale sizes perpendicular parallel direction propagation. They are well modeled an exponential function with characteristic scales 1.34RE (perpendicular) 0.71RE (parallel direction), respectively. Using distribution sizes, derive rate cross-sectional diameters larger than 2RE reference area about 100RE2 That 3 per hour general, 9 under low interplanetary cone angle conditions (<30°), which favorable occurrence magnetosheath.