On the balance between plasma and magnetic pressure across equatorial plasma depletions

  • In magnetized plasmas such as the ionosphere, electric currents develop in regions of strong density gradients to balance the resulting plasma pressure gradients. These currents, usually known as diamagnetic currents decrease the magnetic pressure where the plasma pressure increases, and vice versa. In the low‐latitude ionosphere, equatorial plasma depletions (EPDs) are well known for their steep plasma density gradients and adverse effect on radio wave propagation. In this paper, we use continuous measurements of the magnetic field and electron density from the European Space Agency's Swarm constellation mission to assess the balance between plasma and magnetic pressure across large‐scale EPDs. The analysis is based on the magnetic fluctuations related to diamagnetic currents flowing at the edges of EPDs. This study shows that most of the EPDs detected by Swarm present a decrease of the plasma pressure relative to the ambient plasma. However, EPDs with high plasma pressure are also identified mainly in the vicinity of the SouthIn magnetized plasmas such as the ionosphere, electric currents develop in regions of strong density gradients to balance the resulting plasma pressure gradients. These currents, usually known as diamagnetic currents decrease the magnetic pressure where the plasma pressure increases, and vice versa. In the low‐latitude ionosphere, equatorial plasma depletions (EPDs) are well known for their steep plasma density gradients and adverse effect on radio wave propagation. In this paper, we use continuous measurements of the magnetic field and electron density from the European Space Agency's Swarm constellation mission to assess the balance between plasma and magnetic pressure across large‐scale EPDs. The analysis is based on the magnetic fluctuations related to diamagnetic currents flowing at the edges of EPDs. This study shows that most of the EPDs detected by Swarm present a decrease of the plasma pressure relative to the ambient plasma. However, EPDs with high plasma pressure are also identified mainly in the vicinity of the South Atlantic magnetic anomaly. From the electron density measurements, we deduce that such an increase in plasma pressure within EPDs might be possible by temperatures inside the EPD as high as twice the temperature of the ambient plasma. Due to the distinct location of the high‐pressure EPDs, we suggest that a possible heating mechanism might be due to precipitation of particle from the radiation belts. This finding corresponds to the first observational evidence of plasma pressure enhancements in regions of depleted plasma density in the ionosphere.show moreshow less

Export metadata

Additional Services

Share in Twitter Search Google Scholar Statistics
Metadaten
Author details:Juan Rodriguez-ZuluagaORCiDGND, Claudia StolleORCiDGND, Y. YamazakiORCiD, H. Lühr, J. ParkORCiD, L. ScherliessORCiD, J. L. ChauORCiD
DOI:https://doi.org/10.1029/2019JA026700
ISSN:2169-9402
Parent title (English):Journal of geophysical research : Space physics
Publisher:American Geophysical Union
Place of publication:Washington
Document type:Article
Language:English
Date of first publication:2019/06/25
Year of completion:2019
Release date:2021/01/12
Tag:diamagnetic currents; equatorial plasma depletions; magnetic pressure; plasma pressure; spread F
Volume:124
Issue:7
Page number:9
First page:5936
Last Page:5944
Funder:German Research Foundation (DFG)German Research Foundation (DFG) [(SPP) 1788]; Humboldt Research Fellowship for Experienced Researchers from the Alexander von Humboldt FoundationAlexander von Humboldt Foundation; DFGGerman Research Foundation (DFG) [SPP 1788, CH 1482/1-1]
Organizational units:Mathematisch-Naturwissenschaftliche Fakultät / Institut für Physik und Astronomie
DDC classification:5 Naturwissenschaften und Mathematik / 53 Physik / 530 Physik
Peer review:Referiert
Publishing method:Open Access / Green Open-Access