Physics of auroral phenomena : proceedings of the 36th Annual seminar, Apatity, 26 February – 01 March, 2013 / [ed. board: A. G. Yahnin, A. A. Mochalov]. - Апатиты : Издательство Кольского научного центра РАН, 2013. - 215 с. : ил., табл.

Physics o f Auroral Phenomena", Proc. XXXVI Annual Seminar, Apatity, pp. 159 -162, 2013 © Kola Science Centre, Russian Academy of Science, 2013 Polar Geophysical Institute A MODEL STUDY OF THE INFLUENCE OF ARTIFICIAL HEATING OF THE NIGHTTIME HIGH-LATITUDE IONOSPHERE ON THE SPATIAL DISTRIBUTIONS OF THE IONOSPHERIC PARAMETERS G.I. M ingaleva, V.S. M ingalev Polar G eophysical Institute, Apatity, Russia, e-mail: m ingalev@pgia.ru Abstract. A mathematical model o f the high-latitude ionosphere, developed earlier in the Polar Geophysical Institute, is utilized to calculate three-dimensional distributions of ionospheric parameters in the high-latitude F layer, modified by the action of the ionospheric high-frequency heating facility near Tromso, Scandinavia when it is located on the night side of the Earth. The results of the numerical simulation indicate that artificial heating of the ionosphere by powerful HF waves ought to influence noticeably on the large-scale spatial structure of the nighttime high-latitude F-region ionosphere. Introduction It is well known that high-power high-frequency radio waves, pumped into the ionosphere, cause the variety of physical processes in the ionospheric plasma. Experiments with high-power, high-frequency radio waves, used for the investigation of the ionospheric plasma’s properties during the last four decades, indicated that powerful HF waves can produce significant large-scale variations in the electron temperatures and densities in the F layer [Utlaut and Violette, 1974; Mantas et al., 1981; Duncan et all., 1988; Honary et al., 1995; Gustavsson et al., 2001; Rietveld et al., 2003; Kosch et al., 2007; Pedersen et al., 2008]. To investigate the response o f the high-latitude F region to a powerful HF wave and the role of specific features of the high-latitude ionosphere, mathematical models may be utilized. One o f such mathematical models has been developed in the Polar Geophysical Institute [ Mingaleva and Mingalev, 1997]. This model has been used to simulate the influence of the power, frequency, and modulation regime o f HF waves on the expected response of the height profiles of the ionospheric parameters at F-layer altitudes to HF heating [Mingaleva and Mingalev, 2002; 2003; Mingaleva et al., 2003; 2009; 2012]. The purpose of this paper is to examine how high-power high-frequency radio waves, pumped into the high-latitude ionosphere, influence on the three-dimensional distributions of the ionospheric parameters at F-layer altitudes, with the mathematical model developed in the Polar Geophysical Institute being utilized. Numerical model To calculate three-dimensional distributions of the ionospheric parameters in the F-region ionosphere the mathematical model of the convecting high-latitude ionosphere, developed earlier [Mingaleva and Mingalev, 1996; 1998], is applied. The applied numerical model takes into consideration the strong magnetization of the plasma at F- layer altitudes and the attachment of the charged particles of the F-region ionosphere to the magnetic field lines. As a consequence, the F-layer ionosphere plasma drift in the direction perpendicular to the magnetic field В is strongly affected by the electric field E and follows ExB convection paths (or the flow trajectories). In the model calculations, a part of the magnetic field tube of the ionospheric plasma is considered at distances between 100-700 km from the Earth along the magnetic field line. As a consequence of the strong magnetization of plasma at F-layer altitudes, its motion may be separated into two flows: the first, plasma flow, parallel to the magnetic field; the second, plasma drift in the direction perpendicular to the magnetic field. The parallel plasma flow in the considered part of the magnetic field tube is described by the system o f transport equations, which consists of the continuity equation, the equation o f motion for ion gas, and heat conduction equations for ion and electron gases. The temporal history is traced of the ionospheric plasma included in the part of the magnetic field tube moving along the flow trajectory through a neutral atmosphere. By tracing many field tubes of plasma along a set of flow trajectories, we can construct three-dimensional distributions o f ionospheric quantities. Thus, the model produces three-dimensional distributions of the electron density, positive ion velocity, and ion and electron temperatures. It encompasses the ionosphere above 36° magnetic latitude and at distances between 100 and 700 km from the Earth along the magnetic field line for one complete day. The numerical method, boundary conditions, neutral atmosphere composition, utilized electric field distribution, thermospheric wind pattern, and input parameters of the model were in detail described in the study by Mingaleva and Mingalev [1998]. The applied mathematical model takes into account the following heating mechanism, caused by the action of the powerful HF radio waves. The absorption of the heater wave energy is supposed to give rise to the formation of field-aligned plasma irregularities on a wide range of spatial scales. In particular, short-scale field-aligned irregularities are excited in the electron hybrid resonance region. These irregularities are responsible for the anomalous absorption o f the electromagnetic heating wave (pump) passing through the instability region and cause 159