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.
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."
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.
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.