Traveling convection vortices as seen by the SuperDARN HF radars

Two impulsive traveling convection vortex (TCV) events observed simultaneou sly by ground based magnetometers and the SuperDARN HF radars in the prenoo n sector were studied. In both cases, disturbances traveled westward at spe eds of 4-6 km/s. Convection patterns derived from magnetometer measurements and radar observations were overall in reasonable agreement; observed diff erences at some points might be caused by both the nonuniform ionospheric c onductivity distribution and difference in the integration time of the rada r and magnetometer data. For one event, the convection patterns obtained fr om magnetometer data and SuperDARN radar measurements were relatively simpl e; they can be interpreted as a result of the westward motion of a convecti on vortex system associated with a pair of field-aligned currents separated in azimuthal direction. This TCV event was associated with relatively low Pc5 pulsation activity, contrary to the second TCV event that was accompann ied by a train of Pc5 magnetic pulsations of large amplitude. Convection pa tterns for the second event were complicated. a simple scenario for the int erpretation of the generation of TCVs and Pc5 pulsations is suggested. A su dden impulse in the solar wind dynamic pressure produces disturbances on se veral boundaries of magnetospheric plasma: on the magnetopause, the LLBL in ner edge, and the plasma sheet inner edge. These boundaries are elastic so that surface waves can propagate along them. The high-latitude wave is resp onsible mainly for TCVs, whereas the low-latitude waves may be responsible for excitation of Pc5 field line resonance pulsations. The scenario explain s important features of both TCV events and Pc5 pulsations: both phenomena appear simultaneously and show westward (eastward) propagation, but the TCV s are observed at latitudes close to the LLBL inner edge, whereas the Pc5 p ulsations occur at lower latitudes, close to the inner boundary of the plas ma sheet.