DXERS UNLIMITED SPECIAL REPORT
THE X14 SOLAR EVENT: APRIL 15, 2001
By Arnie Coro CO2KK
Send your comments, questions and ideas to: arnie@radiohc.org
The second-largest solar flare this solar cycle, a "class X14" x-ray flare, was observed departing active sunspot Region 9415 on April 15 at 13:49 UTC. Region 9415 will be known from now on as one of the super-power active sunspot regions of solar cycle 23. A radio blackout in the sunlit hemisphere followed.
Several Cuban radio amateurs with whom I was having an island-wide
roundtable on the 40 meter band told me later that my signals just
disappeared when the x-ray and ultraviolet radiation storm impacted upon the
upper atmosphere, starting phase one of the impact that a major flare has on
radio communications.
Phase two, the following geomagnetic storm, will probably be in progress by the time you are picking up this edition of Dxers Unlimited or maybe later. Solar active region 9415 has now rotated beyond the west limb of the Sun. The activity and morphological structure of this region will undoubtedly be the subject of intense study and scientific interest for years to come, as it had a very peculiar magnetic configuration of the sunspot group, which is very rarely seen, and which was probably what caused such major flare activity. (Photo from LASCO)
Well, we were certainly lucky once again amigos, having this region produce such an intense solar x-ray flare when very near to the west limb of the Sun. Had it occurred when region 9415 was right at the center of the solar disk, in a geoeffective position... then we might have seen many world wide telecommunications service providers running crazily to try to restore satellite based systems... And, we had the huge flare from region 9393, the X22 one -- the most powerful X ray solar flare ever recorded -- happening when region 9393 was not in a geoeffective position, and now the also huge X14 flare from 9393 occurs when that region was almost turning around... Well, I certainly should say that Planet Earth was twice lucky during this active phase of the solar cycle... Had either of those two flares happened from a group of sunspots that were looking right at the Earth, we would certainly still be assessing the damages to satellites, power distribution systems and submarine cables!!!
More comments about the latest X14 flare, which we had the opportunity to observe right as it was developing. This event was associated with exceptionally loud radio bursts. My ten meter band receiver was hitting S9 on the meter picking up the solar noise bursts. The flare also also produced a prompt and spectrally hard proton event in the near-Earth space environment. Although this increased radiation poses no threat to humans on the surface of the Earth, according to space experts, astronauts may have been required to take radiation avoidance measures.
Spacecraft may also experience increased incidences of anomalous events such as single event upsets, phantom commands, star-tracker problems, etc. Space weather analysts are currently looking at the x-ray data from this flare. It is possible this flare (which at an X14 level would probably rank among the top 4 of the largest x-ray flares in recorded history) may have even been larger than that. There is a rumor floating around the professional community that suggests this flare may have been even larger than the estimated X22 flare earlier this month from departed active Region 9393. Once all of the x-ray data has been fully analyzed, it will be more possible to determine quantitatively where this flare ranks in history.
This major flare may have produced a coronal mass ejection that could conceivably result in a minor impact on geomagnetic and auroral activity on or near 18 April, as I said before. The very poor location of the flare on the west limb of the Sun, at a non-geoeffective position, probably has sent virtually all of the ejected mass far to the west of the Earth.
Arnie Coro CO2KK
Havana, Cuba
April 17, 2001
Postal address:
Arnie Coro, "Dxers Unlimited"
Radio Havana Cuba, Havana, CUBA
e-mail: arnie@radiohc.org
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