Tag Archiv: 上海gm干磨店

Modeling the wave power distribution and characterisitics of plamaspheric hiss

first_imgWe simulate the spatial and spectral distributions of plasmaspheric hiss using a technique that involves extensive ray tracing. The rays are injected in the equatorial chorus source region outside the plasmasphere, are power weighted as a function of L-shell, frequency, and wave normal angle, so as to represent the chorus source distribution, and are propagated throughout the simulation domain until the power in each ray is effectivelyextinguished due to Landau damping. By setting up a large number of virtual observatories, the rays passing each observation location are counted, and a distribution isconstructed. Our simulated plasmaspheric hiss spectrum reproduces the main observed features, including the lower and upper frequency cutoffs, the behavior of the bandwidth as a function of L-shell, the spatial extent, and even the two-zone structure of hiss, although the intensity is lower than observed. The wave normal distribution shows that at high latitudes, the wave normals are predominantly oblique, but near the equator, the wave normal distribution can be either predominantly field-aligned (lower L shells), or bebimodal, having a maximum in the field-aligned direction, and another maximum at very oblique angles, comprised of those rays that have broken out of their cyclical trajectories. This distribution of wave normals seems to reconcile the apparently contradictory observations that have been reported previously.last_img read more

Rugby: O’Donnell retains place in Munster starting 15

first_imgBJ Botha replaces Steven Archer and tighthead, while behind them O’Connell forms a second row partnership with Billy Holland.O’Mahony’s return at blindside sees CJ Stander move to number 8.Tomorrow evenings game kicks off at 5 o’clock at the Sportsground. Anthony Foley’s side lie 3rd in the League standings with Connacht in 6th. Tipperary’s Tommy O’Donnell will line out for Munster in their Pro 12 clash with Connacht on New Years Day.The Cahir man retains his place at openside in a starting 15 which shows five changes from the side which started against Leinster.Internationals Simon Zebo, Paul O’Connell and captain Peter O’Mahony all return to the starting fifteen.last_img