This is how the trouble maker looks: the complicated sunspot on the solar surface (grey image) holds magnetic tubes that reach high into the solar atmosphere (yellow image). The solar structure became unstable releasing a light flash around Sept 6, 12:00UT. It is a flash over the entire spectrum: radio waves, visible light, extreme UV, x-rays, gamma. It takes light only 8 minutes to bridge the distance Sun-Earth. The last flash of a similar strength happened on 2006, Dec 5. The most recent flare stronger than that of yesterday occurred on 2005, Sept 7 - exactly 12 years ago and was almost twice as strong.
Our antennas in Humain captured the radio part of the flash. It is seen as a bright structure in a Frequency - Time graph. A bright area in the graph means that the flash was very intense in that particular frequency at that particular time. If you have some imagination, you could recognize Godzilla in it.
At the same time, the GNSS navigation research group was also alerted by their Solar Radio Burst warning system. They saw 'scintillations', i.e. fluctuations in GNSS signals above Europe. GNSS signals pass through the Earth's atmosphere that is impacted by the light flash. These scintillations might disturb the navigation system.
The team in charge of the operations of the PROBA2 satellite were even more excited. At the moment of the light flash, the EUV spectograph LYRA was running a special observation campaign with one of its spare units. This exceptional observation could maybe shed a light on the mechanisms that triggers a flash in the LYRA frequency.
Together with the light flash, the Sun also expelled a plasma cloud. The Space Weather Service Centre of the STCE estimated the arrival second half of Sept 8. The picture below shows the cloud: it is the white structure. You see it is much bigger than the Sun, the yellow ball in the middle. Clouds are indeed HUGE.
By the way, in the news item 'Weather in space is picking up' we mentioned the really fat Sept 4 cloud. It arrived, on Sept 6 around 23:00UT. The local K Dourbes and NOAA Kp reached the level '4' on a scale ranging from 0 to 9.
More science on the radio part.
More science on the GNSS part.
To the Solar Radio Burst Alert page.
