The Solar Maxiumum is Coming!
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Air Force Research Laboratory
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Kirtland AFB, NM 87117-5770CONTACT: Beth Fullerton
PHONE: (781) 377-7111VS RELEASE NO. 98-21
Released: June 25, 1998
SUNSPOT, N.M. -- The Solar Maximum is the peak of a cyclical phenomenon on the sun that occurs every eleven years; it is a period of maximum solar activity that lasts for two or more years.
Being able to predict when the sun will produce the activity which can create more auroras, as well as generate highly energetic particles and geomagnetic activity, is crucial because this heightened activity can interfere with communication satellites, and in extreme cases, destroy them. Also, it can interfere with ground-based radar and radio communications.
Usually, radio and radar communication can bounce off of the ionosphere as if it were a mirror reflecting a signal. These transmissions off of a "flat" surface can be predicted. When Solar Maximum occurs, the ionosphere acts like a corrugated surface, and predicting where a signal will land becomes difficult. The ionosphere can also become opaque to certain frequencies, making communications with satellites difficult or impossible.
Air Force Research Laboratory (AFRL) scientists have found a new technique to forecast the Solar Maximum.
In a paper presented at the spring meeting of the American Geophysical Union in Boston last month, the Space Hazards Branch of the Battlespace Environment Division of the Space Vehicles Directorate identified the first reliable precursor to the maximum of solar activity that will occur near the turn of the century.
A study of the sun's long-term variation of emission features seen in Fe XIV, an ion that is found throughout the solar corona at temperatures around 3 to 4 million degrees Fahrenheit, has shown that, prior to Solar Maximum, emission features appear near 55 degrees latitude in both hemispheres and begin to move toward the poles at a rate of 9 to 12 degrees of latitude per year.
This motion is maintained for a period of 3 or 4 years, at which time the emission features disappear at the poles. This phenomenon, which represents the fastest global motion of any kind on the sun that is sustained for such an interval, has been referred to as the "Rush to the Poles."
Looking at these measurements, the maximum of solar activity, as represented by the number of sunspots on the sun, occurs approximately 14 months before the features reach the poles.
In early 1997, emission features appeared near 55 degrees latitude, and subsequent observations have shown that these features are moving toward the poles. This then is the Rush to the Poles that heralds the next Solar Maximum.
Based on previous observations, these features will reach the poles sometime between March 2000 and January 2001, which results in a prediction for Solar Maximum of between January and November 1999, substantially earlier than some other predictions.
Predicting this phenomenon is important for the Air Force and the public in general. Since the last Solar Maximum in 1989, we rely more than ever on satellites and the information they provide.
"In addition to the disruption to Air Force radar, communications and satellite operations, solar activity can and has produced electrical blackouts that affect millions of people," says Dr. Dick Altrock, AFRL's astrophysicist at the National Solar Observatory, in Sunspot, N.M.