GEOMAGNETIC VARIATIONS IN THE FREQUENCY RANGE 2.5–12 HZ IN THE IONOSPHERIC F LAYER AS MEASURED BY SWARM SATELLITES Journal title: Solar-Terrestrial Physics Authors: Yagova N. V., Fedorov E. N., Pilipenko V. A., Mazur N. G., Martines-Bedenko V. A. Subject(s): Physics, Atmospheric Sciences