1999/06/29 by N. F. Blagoveshchenskaya, V. A. Kornienko, Blagoveshchenskaya, N. F. +15
Earth and Planetary Sciences · Physics and Astronomy · #Earthquake Detection and Analysis #FOS: Physical sciences #Ionosphere and magnetosphere dynamics #Plasma Physics (physics.plasm-ph) #Solar and Space Plasma Dynamics #Space Physics (physics.space-ph)
paper · pdf · doi:10.48550/arxiv.physics/9906057
openalex publication_date 1999/06/29 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
Experimental results from Tromso HF pumping experiments in the nightside auroral E region are reported. We found intriguing evidence that a modification of the ionosphere-magnetosphere coupling, due to the effects of powerful HF waves beamed into an auroral sporadic E layer, can lead to a local intensification of the auroral activity. Summarizing multi-instrument ground-based observations and observations from the IMP 8 and IMP 9 satellites, one can distinguish the following peculiarities related to this auroral activation: modification of the auroral arc and its break-up above Tromso; local changes of the horizontal currents in the vicinity of Tromso; increase of the electron temperature and ion velocities at altitudes above the HF pump reflection level; distinctive features in dynamic HF radio scatter Doppler spectra; pump-induced electron precipitation; substorm activation exactly above Tromso. The mechanisms of the modification of the ionosphere-magnetosphere coupling through the excitation of the turbulent Alfven boundary layer between the base of the ionosphere (~100 km) and the level of sharp increase of the Alfven velocity (at heights up to one Earth radius), and the formation of a local magnetospheric current system are discussed. The results suggest that a possible triggering of local auroral activation requires specific geophysical conditions.