ATRONOMY – OLAR PHYIC (28) CALCULATOR
Plasmasphere Radius
A precise tool.
What is the Plasmasphere Radius & How does it work?
The plasmasphere is a toroidal region of relatively dense, cold plasma that co‑rotates with Earth’s magnetic field, extending from the ionosphere out to several Earth radii.
Its outer boundary, often called the plasmapause, contracts during periods of heightened geomagnetic activity and expands when the magnetosphere is quiet.
R_{ps}=\left(5-0.5\,K_{p}\right)\,R_{E}
R_{ps} = plasmasphere radius, K_{p} = planetary K‑index, R_{E} = Earth radius
By inserting the observed Kp index and the known Earth radius, the simple linear model provides a quick estimate of the plasmasphere’s outer limit in kilometers.
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Frequently Asked Questions
What is the plasmasphere?
The plasmasphere is a toroidal region of dense, cold plasma that surrounds Earth, co-rotating with its magnetic field.
How does the Kp index affect the plasmasphere radius?
A higher Kp index results in a smaller plasmasphere radius as it contracts during geomagnetic storms.
What is the formula used to calculate the plasmasphere radius?
The formula is Rps = (5 – 0.5 * Kp) * RE, where Rps is the plasmasphere radius, Kp is the planetary K-index, and RE is Earth’s radius.
Can you explain what the plasmapause is?
The plasmapause is the outer boundary of the plasmasphere that contracts during geomagnetic storms and expands when the magnetosphere is quiet.
What factors determine the size of the plasmasphere?
The size of the plasmasphere is determined by the planetary K-index and Earth’s radius, with geomagnetic activity affecting its boundaries.
Results are for informational purposes only and do not constitute professional advice.