The excitement about the approaching Solar Max received a boost at about
15:25 UTC (11:25 a.m. EDT) on June 6, 2000; a large x-ray flare occurred
together with a large coronal mass ejection (CME) that ejected billions of
tons of plasma into space on a direct course to impact Earth. Solar flares
are classified by their peak x-ray intensity and this event was of the highest
classification, a class X flare. Activity started with some M flares on June
1, followed by an X1 flare on June 6 (1339 UTC). But the flare related to
the CME was an X2 at 1525 UTC.
The NASA ACE real-time solar wind data indicated there was an Interplanetary
shock passage on June 8 at 0841 UTC, giving about a half hour warning that
a geomagnetic storm (G3) was possible.
Strong geomagnetic storm levels, reaching category G3 on the NOAA Space Weather
Scales, occurred as predicted on June 8-9.
We expect that this storm caused some or all of the following: voltage
corrections on power system grids trigger alarms on protection devices; high
"gas-in-oil" transformer readings; spacecraft surface charging, increased
drag, and orientation problems; HF (high-frequency) radio propagation
intermittent; intermittent low-frequency radio navigation and satellite
navigation problems; the aurora visible as low as 50 degrees.
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The large, complex sunspot region on the face of the Sun that produced the
X-class flares also produced several radio blackouts reaching category R3
and a low level solar radiation storm of S1 level. The activity sparked quite
a bit of public interest: 1.3 million hits on
our website were recorded on June 8.
"Finally, the Sun is starting to flex its muscles," solar forecaster Dave
Speich commented.
June 7, 2000 -- Yesterday the orbiting Solar and Heliospheric
Observatory (SOHO) recorded
a powerful series of solar eruptions including a full-halo coronal mass ejection
(CME).
"The halo CME was magnificent," says Gary Heckman, a space weather forecaster
at the NOAA Space Environment Center. "Based on [the characteristics of the
eruption], this looks like a sure bet to produce a geomagnetic storm."
The velocity of the ejected material was at least 908 km/s, says Dr. Simon
Plunkett, an operations scientist with the SOHO coronagraph team at the Naval
Research Laboratory and the Goddard Space Flight Center. "The CME should
reach Earth in a little less than 48 hours. This would put its arrival around
midday on Thursday, June 8."
A Double Whammy
The June 6, 2000, coronal mass ejection was accompanied by two of the most
intense solar flares since a brilliant eruption in February 2000.
"CMEs can occur without a flare," says Dr. David Hathaway, a solar physicist
at the Marshall Space Flight Center, "but today is the more typical case
where a flare is also part of the eruption.
"Solar flares and CMEs occur whenever there's a rapid, large-scale change
in the Sun's magnetic field. The solar active region that produced the eruptions
[on June 6] had a complicated magnetic configuration - oppositely directed
magnetic fields were seen right next to each other."
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Does this spate of solar activity means that Solar Maximum has finally
arrived?
"This is an indication that solar maximum is upon us," says Hathaway. There
is a common misconception that "Solar Max" is a single episode of high activity.
Not so, Hathaway cautions. The solar maximum will last over an extended period
of time, perhaps as long as two years interspersed with many powerful solar
flares and CMEs.
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Below:
Solar Flares are classified by their x-ray flux in the 1.0 - 8.0 Angstrom
band as measured by the NOAA GOES-8 satellite. On June 6, 2000, two solar
flares from active region 9026 registered as powerful X-class eruptions.
Footnotes (prediction)
