Estimated Kp indices

The estimated Kp indices of the last 28 days

The estimated planetary K index is obtained from a network of magnetometer stations at mid-latitudes in the western hemisphere. By monitoring the variation of the magnetic field these stations record the effects of the auroral electrojet current system, the magnetospheric ring current and field-aligned currents that connect the ionosphere to the magnetosphere.

Mid-latitude stations are rarely directly under intense horizontal current systems, thus magnetic perturbations can be dominant in either the H or D component. The Kp index utilizes both these perturbations by taking the logarithm of the largest excursion in H or D over a 3-h period. The scale ranges from 0 (magnetically quiet) to 9 (very disturbed).

Also available: previous estimated KP indices, sorted by Carrington Rotation Numbers

Plots of the last 5 Carrington Rotation Cycles including the current cycle.
Directory listing with previous estimated Kp-plots, sorted after Carrington Rotation Cycles .

These images are prepared based on estimated Kp indices provided by the Space Environment Center, NOAA.

Last updated 21 Oct 98, vb