TY - JOUR

T1 - Ionospheric HF pump wave triggering of local auroral activation

AU - Blagoveshchenskaya, N. F.

AU - Kornienko, V. A.

AU - Borisova, T. D.

AU - Thidé, B.

AU - Kosch, Mike J.

AU - Rietveld, M. T.

AU - Mishin, E. V.

AU - Lukýanova, R. Yu.

AU - Troshichev, O. A.

N1 - Copyright (2001) American Geophysical Union.

PY - 2001/12

Y1 - 2001/12

N2 - Experimental results from ionospheric HF pumping experiments in the nightside auroral E region above Tromsø 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 observations during two consecutive nights, one can distinguish the following peculiarities related to this auroral activation: a modification of the auroral arc and its breakup above Tromsø, local changes in the horizontal currents above Tromsø, a burst-like increase of the electron density and temperature, a large increase in the ion temperature in a wide altitude range and in the north-south component of the electric field, distinctive features in dynamic HF radio scatter Doppler spectra, pump-induced electron precipitation, and substorm activation exactly above Tromsø. We discuss the modification of the ionosphere-magnetosphere coupling in terms of the excitation of a turbulent Alfvén boundary layer between the base of the ionosphere (∼100 km) and the level of sharp increase of the Alfvén velocity (at heights up to one Earth radius), and the formation of a local magnetospheric current system. The results suggest that a possible triggering of local auroral activation requires specific geophysical conditions.

AB - Experimental results from ionospheric HF pumping experiments in the nightside auroral E region above Tromsø 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 observations during two consecutive nights, one can distinguish the following peculiarities related to this auroral activation: a modification of the auroral arc and its breakup above Tromsø, local changes in the horizontal currents above Tromsø, a burst-like increase of the electron density and temperature, a large increase in the ion temperature in a wide altitude range and in the north-south component of the electric field, distinctive features in dynamic HF radio scatter Doppler spectra, pump-induced electron precipitation, and substorm activation exactly above Tromsø. We discuss the modification of the ionosphere-magnetosphere coupling in terms of the excitation of a turbulent Alfvén boundary layer between the base of the ionosphere (∼100 km) and the level of sharp increase of the Alfvén velocity (at heights up to one Earth radius), and the formation of a local magnetospheric current system. The results suggest that a possible triggering of local auroral activation requires specific geophysical conditions.

KW - heating

KW - ASC DCS-publications-id

KW - art-231

KW - DCS-publications-credits

KW - dasi

KW - iono

KW - scasi

KW - DCS-publications-personnel-id

KW - 7

U2 - 10.1029/2001JA900002

DO - 10.1029/2001JA900002

M3 - Journal article

VL - 106

SP - 29071

EP - 29089

JO - Journal of Geophysical Research

JF - Journal of Geophysical Research

SN - 0148-0227

IS - A12

ER -