Slot Region Plot Summary

The summary is updated every hour.

No data is collected by operational spacecraft in the Slot Region and so data is plotted from RBSP-A as the spacecraft crosses 8,000 km altitude (L* = 2.2) near the equator.

Each web page has 6 plots in the following general form:

• Top left – the electron flux (colour coded) as a function of L* and time, at a selected energy and pitch angle of 88 degrees taken from the BAS-RBM. Here L* is very approximately equal to the distance from the centre of the Earth along the equatorial plane measured in Earth radii. L* is part of a magnetic coordinate system based on the drift path of electrons. To a first approximation electrons drift around the Earth following a path of constant magnetic field which corresponds to a fixed value of L*. As the geomagnetic field is stronger on the dayside of the Earth electrons on the same drift path are farther away from the Earth on the dayside and closer on the nightside. Thus a satellite at geostationary orbit samples electrons with a lower L* on the dayside. As the electron flux usually peaks near L* = 4.5 – 5.0 satellites at geostationary orbit are exposed to a higher electron flux on the dayside. The location of the scientific satellite RBSP is shown as a black line in this coordinate system. Note that RBSP is in an elliptical orbit near the equatorial plane but does not extend out to geostationary orbit. When the outer boundary of the geomagnetic field lies inside L* = 8 it is indicated by a solid white line.
• Middle left – (in red) the electron flux at 8,000 km altitude (L* = 2.2) from the model, and (in black) the electron flux measured by RBSP when it crosses L* = 2.2, when available. Note that the observed flux is often much higher than the model due to the instrument noise level. The flux only increases substantially when there is an electron injection event.
• Bottom left - the Kp index of geomagnetic activity, colour coded according to activity level.
• Top right – (in red) the solar wind velocity measured by the DSCOVR spacecraft at the Lagrange 1 position in the solar wind and (in black) the z component of the interplanetary magnetic field.
• Middle right – (in red) the solar wind dynamic pressure measured by DSCOVR spacecraft and (in black) the Dst index which is used to identify geomagnetic storms
• Bottom right - the proton flux at 21.25 MeV measured by RBSP when it crosses L* = 2.2. The proton flux is an indicator of a solar energetic particle event.