Degeling, AW;
Rae, IJ;
Watt, CEJ;
Shi, QQ;
Rankin, R;
Zong, Q-G;
(2018)
Control of ULF Wave Accessibility to the Inner Magnetosphere by the Convection of Plasma Density.
Journal of Geophysical Research: Space Physics
, 123
(2)
pp. 1086-1099.
10.1002/2017JA024874.
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Abstract
During periods of storm activity and enhanced convection, the plasma density in the afternoon sector of the magnetosphere is highly dynamic due to the development of plasmaspheric drainage plume (PDP) structure. This significantly affects the local Alfvén speed and alters the propagation of ULF waves launched from the magnetopause. Therefore, it can be expected that the accessibility of ULF wave power for radiation belt energization is sensitively dependent on the recent history of magnetospheric convection and the stage of development of the PDP. This is investigated using a 3-D model for ULF waves within the magnetosphere in which the plasma density distribution is evolved using an advection model for cold plasma, driven by a (VollandStern) convection electrostatic field (resulting in PDP structure). The wave model includes magnetic field day/night asymmetry and extends to a paraboloid dayside magnetopause, from which ULF waves are launched at various stages during the PDP development. We find that the plume structure significantly alters the field line resonance location, and the turning point for MHD fast waves, introducing strong asymmetry in the ULF wave distribution across the noon meridian. Moreover, the density enhancement within the PDP creates a waveguide or local cavity for MHD fast waves, such that eigenmodes formed allow the penetration of ULF wave power to much lower L within the plume than outside, providing an avenue for electron energization.
| Type: | Article |
|---|---|
| Title: | Control of ULF Wave Accessibility to the Inner Magnetosphere by the Convection of Plasma Density |
| Open access status: | An open access version is available from UCL Discovery |
| DOI: | 10.1002/2017JA024874 |
| Publisher version: | http://dx.doi.org/10.1002/2017JA024874 |
| Language: | English |
| Additional information: | ©2018. The Authors. This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited. |
| Keywords: | Science & Technology, Physical Sciences, Astronomy & Astrophysics, FIELD LINE RESONANCES, FINITE IONOSPHERE CONDUCTIVITIES, RADIATION BELT ELECTRONS, RELATIVISTIC ELECTRONS, MAGNETIC PULSATIONS, GEOMAGNETIC STORMS, IMAGE SATELLITE, ALFVEN WAVES, DIPOLE MODEL, EVOLUTION |
| UCL classification: | UCL UCL > Provost and Vice Provost Offices > UCL BEAMS UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences > Dept of Space and Climate Physics |
| URI: | https://discovery-pp.ucl.ac.uk/id/eprint/10046998 |
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