TY  - JOUR
A1  - Rodriguez-Zuluaga, Juan
A1  - Stolle, Claudia
A1  - Yamazaki, Yosuke
A1  - Lühr, H.
A1  - Park, J.
A1  - Scherliess, L.
A1  - Chau, J. L.
T1  - On the balance between plasma and magnetic pressure across equatorial plasma depletions
JF  - Journal of geophysical research : Space physics
N2  - 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 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.
KW  - equatorial plasma depletions
KW  - spread F
KW  - plasma pressure
KW  - magnetic pressure
KW  - diamagnetic currents
Y1  - 2019
U6  - https://doi.org/10.1029/2019JA026700
SN  - 2169-9402
VL  - 124
IS  - 7
SP  - 5936
EP  - 5944
PB  - American Geophysical Union
CY  - Washington
ER  -