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Modeling the effects of cold‐dense and hot‐tenuous plasma sheet on proton ring current energy and peak location
Author(s) -
Lavraud Benoit,
Jordanova Vania K.
Publication year - 2007
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/2006gl027566
Subject(s) - ring current , plasma sheet , plasma , current (fluid) , atomic physics , geomagnetic storm , current density , atmospheric pressure plasma , proton , kinetic energy , physics , materials science , magnetosphere , solar wind , nuclear physics , thermodynamics , quantum mechanics
We have run kinetic ring current simulations with different plasma boundary conditions, but preserving a constant plasma pressure, during a “test” time interval conducive to a storm. Although the energy density of the injected plasma is kept constant, the resulting proton ring current energy is significantly increased as the injected plasma is colder and denser. Investigation of the separate effects of density and temperature shows that (1) ring current strength is primarily controlled by density, and that (2) colder plasma leads to a ring current peak closer to Earth and to midnight, but density has no effect. While cold plasma may convect deeper inside the ring current region, hotter plasma is more subject to magnetic drifts and quickly drifts toward dusk with lower energization. These results support the idea that the presence of cold and dense plasma in the magnetotail may lead to increased ring current during an ensuing storm.