[radioastro] Solar event on 100807 near 18 to 21 UT, at STEREO WAVES

  • From: Victor Herrero <hubbleed@xxxxxxxxx>
  • To: Radio JOVE NASA GSFC <radiojove@xxxxxxxxxxxxxxxxxxxxxx>
  • Date: Sun, 8 Aug 2010 09:52:25 -0700

Solar event on 100807 near 18 to 21 UT, at STEREO WAVES

I attach a detail from the STEREO WAVES spectrum:
http://swaves.gsfc.nasa.gov/data/s-waves-ds/2010/swaves_summary_20100807_c.png

The black time ticks are at 18 and 19 UT.
The white line is at 16 MHz, and the lower edge is near 1 MHz (log scale).

The SWAVES spectrum shows type III radiation lasting for 3 hours and
reaching close to 20 kHz. At 20 kHz, the radiation source is possibly close
to 1 Astronomical Unit from the Sun.

There is also type II (slow negative drifting) radiation, lasting for about
15 minutes at 16 MHz, followed by type IV radiation lasting for about 1.5
hours, in the 10 to 16 MHz band.

Type IV radiation was defined at VHF frequencies, but I think it is
reasonable to extend the definition to lower frequencies: a broad band
continuum that may occur after strong flares, and lasts for hours.

Radio JOVE Observers posted spectra showing slow positive drifting bursts. I
interpret them as caused by CME induced shock waves propagating downwards to
plasma regions of higher density and radiated frequency, mostly during the
early part of the type II event in the 16 to 28 MHz band.

My many thanks to the STEREO/WAVES Team.

The Sun is full of surprises.
My ignorance is vast.

Victor

Attachment: SWAVES_100807_Sun_M1.jpg
Description: JPEG image

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