 Sunspots on the rise, and slow solar
currents
The current sunspot cycle will be above the average but no
record setter, according to SSL's Dr. David Hathaway, Dr. Robert
M. Wilson, and Edwin J. Reichmann. They predict that Cycle 23
will rise faster than normal to its peak, attaining maximum amplitude
sometime during the latter half of 1999 to the first half of
2000, and that it will measure about 170±20 units (yearly
sunspot number). They expect Cycle 23 to continue until sometime
in 2006 when Cycle 24, should begin. (The cycle numbers start
when the Zurich numbering scheme was introduced in 1848.)
Right:
A picture of Jupiter superimposed on the Sun shows the incredible
size of super cells that have eluded detection for more than
20 years. These cells play a role in the movement of sunspots.
Credit: NASA/MSFC.
An active sun can cause geomagnetic storms that endanger satellites
and disrupt communications and power systems on Earth, and can
heat the Earth's outer atmosphere so that spacecraft are exposed
to more atmospheric drag and to greater erosion by atomic oxygen.
Hathaway, Wilson, and Reichmann base their prediction on statistical
variations in geomagnetic indices, the occurrences of high-latitude
spots, the inferred strengths of the sun's polar fields, and
the number of geomagnetically disturbed days in the preceding
cycle.
Hathaway has also found massive circulation patterns that
may play a role in moving sunspots across the face of the Sun.
Like a boiling pot of water, the sun has a complex array of convection
patterns that carry hot gas from the inner sun to the visible
surface, where it radiates its energy, cools, and then flows
back down. The existence of "super cells" flow patterns
that are larger than the planet Jupiter was predicted almost
30 years ago. But the actual discovery was difficult because
these cells are also the slowest, so they were easily lost in
the chaos of shorter, more energetic flows. Using two years worth
of data from the Solar and Heliospheric Observatory, Hathaway
was able to filter out the faster flow patterns and reveal the
super cells.
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