Tuesday, 9 September 2014

Magnetic mapping of the SGO measurements

In geophysics, a widely used concept "L-shell" describes how some given location on the ground maps to the magnetosphere along the magnetic field line. Starting from any given location, and following its magnetic field up to the equator plane of the Earth's magnetosphere, the L-value is the distance to that point in Earth's radii (Wikipedia).

Aeronomy research at the SGO is focused on the effects of the energetic particle precipitation from the magnetosphere to the atmosphere. Our long-term ground based instruments (see the map below), such as riometers and pulsation magnetometers, are ideally located across the most interesting L-shells, covering Van Allen Radiation Belts (L=1.5-2.5 and 4-6), auroral oval (L~6) and even the polar cap (L>10).

Another perspective is to look at the "magnetic conjugate points", i.e., to follow the magnetic field lines all the way down to the ground at the opposite magnetic hemisphere. Unfortunately, our stations mainly map to the Indian sea, making it practically impossible to study exactly the same magnetospheric field-line from two locations. However, there is one extremely close magnetic field linkage between "our" instrumentation at Svalbard, including the EISCAT radar, and the Australian Antarctic research station Davis with wealth of relevant geophysical instrumentation. This linkage must be studied more carefully in the near future ...

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