PFISR and ROPA observations of pulsating aurora

Abstract: Previous observations have shown that pulsating aurora sometimes occurs with patches of a vertical extent that is thinner than would be expected for aurora caused by collisional processes, implying that local ionospheric processes are important in causing the narrow luminosity enhancement. However, Poker Flat Incoherent Scatter Radar (PFISR) data from four pulsating aurora events, during the Rocket Observations of Pulsating Aurora (ROPA) mission in January and February 2007, show that the electron density profile associated with the pulsating patches had a thickness of in all four cases and that, therefore, these are not examples of such thin enhancements. A numerical model of the associated volume emission rates for the night of the ROPA launch supports this conclusion. In the process of modeling the volume emission rates, the PFISR data are inverted to calculate the associated electron energy distribution for comparison with in situ electron measurements from ROPA and the REIMEI satellite. The modeled distribution shows a diffuse plasma sheet population which gradually decreases in energy over the course of the event, resulting in precipitation by the end of the PFISR data interval, in agreement with the ROPA/REIMEI measurements. [Copyright &y& Elsevier]