NW7US Propagation Bulletin Update
20 January 2005 - 1645 UTC
This latest X-class flare, the THIRD LARGEST of this solar cycle (Cycle
23), was incredible. It unleashed an extreme (and very sudden) proton
event, that has nearly caused a complete white-out of various space
weather satellite instruments.
Even so, it has been confirmed that a full-halo coronal mass ejection was
associated with this large and impressive X7 proton flare. Because of the
incomplete data (due to the proton bombardment), it appears that this CME
may be fairly well directed Earthward. But, this could be wrong. Many
teams are working on this one. If the CME is directed mostly Earthward,
the impact could be quite strong. If the orientation at that time of the
interplanetary magnetic field is soutward, (a negative Bz), we could see
the most significant geomagnetic storminess of this entire period of
activity associated with active solar region 720.
The impact of such a CME would be within one to two day. Do remember that
we are also under the influence of a coronal hole. And, we now believe
that the CME expected sometime today has likely arrived just before this
big X7 flare occurred. The solar wind speed had a jump of over 200 km/s.
The Bz, however, remained positive as the wind reached over 900 km/s by
0700 UTC. That's when the sensors became saturated and we lost the
ability to monitor the wind's details.
I'll send out another update later when more details are confirmed.
73 de Tomas, NW7US (AAR0JA/AAA0WA)
: Propagation Editor for CQ, CQ VHF, Popular Communications :
: Creator; live propagation center http://prop.hfradio.org/ :
: Associate Member of Propagation Studies Committee of RSGB :
: US Army Miltary Affiliate Radio Service (MARS) SMD AAA0WA :
: 122.93W 47.67N / Brinnon, Washington USA CN87 CW/SSB/DIGI :
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