Polar Cap Absorption

A polar cap absorption event results from the ionisation of the D-layer of the polar ionosphere by high energy protons. A PCA causes a HF radio blackout for trans polar circuits and can last several days. PCAs are almost always preceded by a major solar flare with the time between the flare event and the onset of the PCA ranging from few minutes to several hours.

See Real Time Riometer Data from Antarctic Stations.

The icon below indicates the estimated absorption in db of a 30 MHz riometer from Casey station in Antarctica. These figures give an indication of the severity of the PCA. The background colour of the icon is red when absorption exceeds 1db and green otherwise.

Details of any current proton event are given below:

(last updated 21 May 2013 21:40 UT)

10MeV Proton/PCA Event Began 23 01 2012 0520UT and is in progress 10MeV Proton/PCA Event Ended 27 01 2012 0930UT 10MeV Proton/PCA Event Began 27 01 2012 1855UT and is in progress 10MeV Proton/PCA Event Ended 31 01 2012 0545UT 10MeV Proton/PCA Event Began 07 03 2012 0445UT and is in progress 10MeV Proton/PCA Event Ended 12 03 2012 2030UT 10MeV Proton/PCA Event Began 13 03 2012 0725UT and is in progress 10MeV Proton/PCA Event Ended 13 03 2012 0810UT 10MeV Proton/PCA Event Began 13 03 2012 1800UT and is in progress 10MeV Proton/PCA Event Ended 15 03 2012 0605UT 10MeV Proton/PCA Event Began 17 05 2012 0200UT and is in progress 10MeV Proton/PCA Event Ended 18 05 2012 1410UT 10MeV Proton/PCA Event Began 27 05 2012 0455UT and is in progress 10MeV Proton/PCA Event Ended 27 05 2012 0620UT 10MeV Proton/PCA Event Began 27 05 2012 0705UT and is in progress 10MeV Proton/PCA Event Ended 27 05 2012 0800UT 10MeV Proton/PCA Event Began 27 05 2012 0835UT and is in progress 10MeV Proton/PCA Event Ended 27 05 2012 1215UT 10MeV Proton/PCA Event Began 16 06 2012 2200UT and is in progress 10MeV Proton/PCA Event Ended 16 06 2012 2235UT 10MeV Proton/PCA Event Began 07 07 2012 0350UT and is in progress 10MeV Proton/PCA Event Ended 07 07 2012 1905UT 10MeV Proton/PCA Event Began 07 07 2012 1935UT and is in progress 10MeV Proton/PCA Event Ended 07 07 2012 2105UT 10MeV Proton/PCA Event Began 09 07 2012 0105UT and is in progress 10MeV Proton/PCA Event Ended 09 07 2012 1425UT 10MeV Proton/PCA Event Began 12 07 2012 1825UT and is in progress 10MeV Proton/PCA Event Ended 14 07 2012 2235UT 10MeV Proton/PCA Event Began 14 07 2012 2320UT and is in progress 10MeV Proton/PCA Event Ended 15 07 2012 0145UT 10MeV Proton/PCA Event Began 17 07 2012 1650UT and is in progress 10MeV Proton/PCA Event Ended 21 07 2012 0205UT 10MeV Proton/PCA Event Began 23 07 2012 1350UT and is in progress 10MeV Proton/PCA Event Ended 23 07 2012 1545UT 10MeV Proton/PCA Event Began 23 07 2012 1615UT and is in progress 10MeV Proton/PCA Event Ended 23 07 2012 2325UT 10MeV Proton/PCA Event Began 24 07 2012 0630UT and is in progress 10MeV Proton/PCA Event Ended 24 07 2012 0800UT 10MeV Proton/PCA Event Began 24 07 2012 0925UT and is in progress 10MeV Proton/PCA Event Ended 24 07 2012 1215UT 10MeV Proton/PCA Event Began 24 07 2012 1240UT and is in progress 10MeV Proton/PCA Event Ended 24 07 2012 1315UT 10MeV Proton/PCA Event Began 24 07 2012 1340UT and is in progress 10MeV Proton/PCA Event Ended 24 07 2012 1405UT 10MeV Proton/PCA Event Began 01 09 2012 1325UT and is in progress 10MeV Proton/PCA Event Ended 01 09 2012 2335UT 10MeV Proton/PCA Event Began 02 09 2012 0135UT and is in progress 10MeV Proton/PCA Event Ended 02 09 2012 0535UT 10MeV Proton/PCA Event Began 02 09 2012 0625UT and is in progress 10MeV Proton/PCA Event Ended 03 09 2012 0635UT 10MeV Proton/PCA Event Began 28 09 2012 0245UT and is in progress 10MeV Proton/PCA Event Ended 28 09 2012 0630UT 10MeV Proton/PCA Event Began 16 03 2013 1855UT and is in progress 10MeV Proton/PCA Event Ended 17 03 2013 0305UT 10MeV Proton/PCA Event Began 17 03 2013 0505UT and is in progress 10MeV Proton/PCA Event Ended 17 03 2013 0605UT 10MeV Proton/PCA Event Began 11 04 2013 1005UT and is in progress 10MeV Proton/PCA Event Ended 12 04 2013 2105UT 10MeV Proton/PCA Event Began 15 05 2013 1315UT and is in progress 10MeV Proton/PCA Event Ended 18 05 2013 1340UT

(last updated 21 May 2013 21:40 UT)

No proton event in progress

Current proton fluxes are as follows:

(last updated 21 May 2013 21:40 UT)

GOES Gp satellite Energetic Proton Flux (Courtesy of SWPC, Boulder Colorado, USA) Units: Protons/cm2-s-sr 10MeV and 100MeV threshold proton flux level is 10 proton flux units (PFU) Date: 21 05 2013 2130 UT 1MeV Proton flux: 1.51e+01 5MeV Proton flux: 1.16e+00 10MeV Proton flux: 2.41e-01 100MeV Proton flux: 1.84e-02

Proton flux data for this page are provided by the US Space Environment Service (SEC). For more details see Today's Space Weather from Space Weather Prediction Center in Boulder.