STARE and SABRE observations of a Pc 5 pulsation with large azimuthal wave number during a storm period

摘要: The STARE (Scandinavian Twin Auroral Radar Experiment) and SABRE (Sweden Britain systems have been used to estimate electric fields in the high-latitude ionosphere during a Pc 5 geomagnetic pulsation. With each coherent radar system, measurements are made over large area (∼200,000 km²) with good spatial resolution of 20×20 km². Combined, cover range L value from 4.4 8.8. observations were local magnetic afternoon hours recovery phase storm. period is essentially constant latitude (geographic 64.6°–70.2°), having mean 365 s for both toroidal poloidal components. azimuthal wave number (∼24), velocity directed equatorward westward. When mapped dipole field into equatorial plane, at = 6.14, wavelengths found be 9177–9585 km view. pulsation amplitude <8 mV m−1. maximizes 69° geographic 67.6° (corresponding 66.4°–66°). variation resembles gradient curvature drift energetic hot protons. compared instability compressional shear Alfven mode high β plasma.