Solar Activity Report for 4/27/05
- ** Aurora Watch In Effect **
There's actually something interesting to talk about tonight, as a CME
is on the way to Earth. On the 25th, a fairly weak but unmistakable
CME was kicked off by the sun, and there was definitely a halo
component to it. What makes this one really interesting is that it
wasn't associated with a sunspot. Instead, it was most likely caused
by a solar filament collapse. Filaments are gigantic loops of gas
that are suspended above the visible surface of the sun by a magnetic
field. If the magnetic field becomes unstable, the gas in the
filament, being cooler by virtue of being suspended above the
"surface," will come crashing back down. When it impacts the layer of
gas below it, it creates one heck of a splash. The results of the
splash is what's called a Hyder flare, and a CME is often the end
result. The CME from this event is expected to arrive within the next
24 hours. A small coronal hole has also rotated into view. We may
see some high speed solar wind gusts from it on either the 30th or May
1st. There is one sunspot region visible, that being region 756. It
does appear to be growing both in size and magnetic complexity, and
stands at least an outside chance of producing an M-class flare.
The current solar and geomagnetic conditions are :
NOAA sunspot number : 45
SFI : 95
A index : 2
K index : 0
Solar wind speed : 355.5 km/sec
Solar wind density : 2.1 protons/cc
Solar wind pressure : 0.5 nPa
IMF : 3.0 nT
IMF Orientation : 0.4 nT North
GOES-12 Background X-ray Flux level : B1
Conditions for the past 24 hours :
No space weather storms were observed for the past 24 hours.
Forecast for the next 24 hours :
No space weather storms are expected for the next 24 hours.
Solar activity forecast :
Solar activity is expected to be at low levels. Region 756 has the
capability of producing an isolated M-class flare.
Geomagnetic activity forecast :
The geomagnetic field is expected to be at quiet to unsettled levels.
There is a slight chance that the partial halo CME observed on 25-26
April might produce isolated active conditions on 29 April.
Recent significant solar flare activity :