Xray burst - Radio Burst - Coronal Mass Ejection (CME)
Cosmic Ray Forbush Decrease - Magnetic Field Distortion
Pulling together different scientific areas: radio astronomy, cosmic rays, magnetometry
On May 13th, 2005 there was a huge flare on Sun, which produced emissions of various kinds.
First the flare was detected in the X-ray and radio range. The first graph shows the sudden increase in X-ray flux measured
by the GOES satellites.
The second graph shows the same X-ray flux, but with higher time resolution.
This plot shows the radio burst produced by the flare. It was recorded at UFRO at frequencies between 18 and 28 MHz and captured by 'The Internet Jupiter/Solar Radio Observatory'.
Note that the radio burst is much shorter than the X-ray burst.
Only about half an hour later, the Coronal Mass Ejection (CME) was visible in this SOHO image (structures on the left in the image).
The CME continued to advance in direction of Earth and about 33 hours later it hit Earth's atmosphere.
This graph shows the proton, electron flux recorded by the GOES satellites, aswell as the magnetic field of Earth recorded
by these satellites and the calculated "planetary index" Kp. Something noteworthy: The proton flux already started to increase
only a few hours after the flare occured, indicating that those particles were traveling at really high speeds.
When the shock wave hit Earth's atmosphere, the proton flux peaked, the electron flux and of course the magnetic field of Earth
became highly distorted. This is also the time when Aurora is visible at much lower latitudes than usual.
Another side-effect of the CME passing Earth is a decrease in Cosmic Ray flux due Forbush decrease.
It is clearly visible in the Oulu Neutron Monitor graph: When the CME hit Earth, the magnetic field of the CME deflects the Galactic
Cosmic Rays and the secondary particle flux (Neutrons) decreases. In this graph there is also another Forbush decrease visible, which
was caused by another, not that powerful flare, which CME passed Earth a few days before this event.
And of course the magnetograms of various magnetometers show the impact of the CME and the distrubed magnetic field afterwards.
The maximum distortion of Earth's magnetic field was about 7:00UT on May 15th, 2005 - also the Forbush decrease was at a maximum at this
time. This implies that the particle density of the CME reached the peak at this time (7:00UT).
F is the total intensity, H is the horizontal intensity, both in Nanotesla [nT] (always postive). Z is the vertical intensity in Nanotesla [nT] (positve down).
D is the angle between geographic and magnetic north in minutes ['] (postive east). Declination near Fuerstenfeldbruck and Munich is around 75', that means almost 1°15' East or 1.25° East.
References:
Today's Space Weather
The Internet Jupiter/Solar Radio Observatory
Oulu Neutron Monitor
Magnetometer Fürstenfeldbruck
Last-Modified: Mon, 16 May 2005 19:11:05 GMT
|
