Труды сотрудников ИВМ СО РАН

[Text] / N. V. Erkaev [et al.] // Phys. Plasmas. - 2005. - Vol. 12, Is. 1. - Ст. 12905, DOI 10.1063/1.1833392. - Cited References: 18 . - ISSN 1070-664XРУБ Physics, Fluids & Plasmas

Аннотация: Within the framework of the assumption of large azimuthal wave numbers, the equations for Alfven and slow magnetosonic waves are obtained using frozen-in material coordinates. These equations are specified for the case of a nonuniform magnetic field with axial symmetry. Assuming a meridional polarization of the magnetic field and velocity perturbations, the effects of Alfven wave propagation are analyzed which are related to geometric characteristics of a nonuniform magnetic field: (a) A finite curvature radius of the magnetic field lines and (b) convergence of magnetic field lines. The interaction between the Alfven and magnetosonic waves is found to be strongly dependent on the curvature radius of the magnetic tube and the local plasma beta parameter. The electric field amplitude and the length scale of a wave front are found to increase very strongly in the course of the Alfven wave propagation along a converging magnetic flux tube. Also studied is a temporal decrease of the wave perturbations which is caused by dissipation at the conducting boundary. (C) 2005 American Institute of Physics.


Доп.точки доступа:
Erkaev, N.V.; Еркаев, Николай Васильевич; Shaidurov, V.A.; Semenov, V.S.; Langmayr, D.; Biernat, H.K.

[Text] / N. V. Erkaev [et al.] ; ed. H. K. Biernat // BOUNDARY LAYERS, WAVES AND NON-LINEAR DYNAMICAL PROCESSES. Ser. ADVANCES IN SPACE RESEARCH : ELSEVIER SCIENCE LTD, 2006. - Vol. 37: 35th COSPAR Scientific Assembly (JUL 18-25, 2004, Paris, FRANCE), Is. 3. - P576-580, DOI 10.1016/j.asr.2005.09.002. - Cited References: 7 . - ISBN 0273-1177РУБ Engineering, Aerospace + Astronomy & Astrophysics + Geosciences, Multidisciplinary + Meteorology & Atmospheric Sciences

Аннотация: A ratio of the maximal and minimal cross sections of the magnetic tube (contraction ratio) is a crucial parameter which affects very strongly on reflections of MHD wave pulses propagating along a narrowing magnetic flux tube. In cases of large contraction ratios of magnetospheric magnetic tubes, the wave energy flux at the ionospheric boundary can be rather small. Therefore the dissipation of the wave perturbations can be very weak for each reflection, in spite of a finite conductivity of the planet's ionosphere. The dissipation is stronger for the pulses with shorter wave scales. Because of that, Alfven wave pulses with sufficiently long wave scales have a very small energy loss for each reflection at the conducting ionosphere, and thus, they have many reflections without a noticeable decrease of their amplitude. This effect related to converging magnetic lines is dependent very strongly on the polarization of the Alfven wave. In case of a dipole magnetic field, the effect is most pronounced for wave pulses characterized by velocity and magnetic perturbations in the meridional plane. (C) 2005 COSPAR. Published by Elsevier Ltd. All rights reserved.


Доп.точки доступа:
Erkaev, N.V.; Еркаев, Николай Васильевич; Shaidurov, V.A.; Semenov, V.S.; Biernat, H.K.; Heidorn, D.; Biernat, H.K. \ed.\