Premium
The Polar Wind Modulated by the Spatial Inhomogeneity of the Strength of the Earth's Magnetic Field
Author(s) -
Li Kun,
Förster Matthias,
Rong Zhaojin,
Haaland Stein,
Kronberg Elena,
Cui Jun,
Chai Lihui,
Wei Yong
Publication year - 2020
Publication title -
journal of geophysical research: space physics
Language(s) - English
Resource type - Journals
eISSN - 2169-9402
pISSN - 2169-9380
DOI - 10.1029/2020ja027802
Subject(s) - outflow , earth's magnetic field , polar , solar wind , geophysics , ionosphere , magnetic field , polar wind , field strength , physics , atmospheric sciences , dipole model of the earth's magnetic field , interplanetary magnetic field , geology , astronomy , meteorology , quantum mechanics
When the geomagnetic field is weak, the small mirror force allows precipitating charged particles to deposit energy in the ionosphere. This leads to an increase in ionospheric outflow from the Earth's polar cap region, but such an effect has not been previously observed because the energies of the ions of the polar ionospheric outflow are too low, making it difficult to detect the low‐energy ions with a positively charged spacecraft. In this study, we found an anticorrelation between ionospheric outflow and the strength of the Earth's magnetic field. Our results suggest that the electron precipitation through the polar rain can be a main energy source of the polar wind during periods of high levels of solar activity. The decreased magnetic field due to spatial inhomogeneity of the Earth's magnetic field and its effect on outflow can be used to study the outflow in history when the magnetic field was at similar levels.