Satellite Makes Solar Wind Count

Article excerpt

Like water from a spinning lawn sprinkler, electrically charged particles in the solar wind spiral outward from the sun's corona in continuous streams. Hydrogen and helium make up about 99.9 percent of the wind, with a medley of heavy elements filling in the rest. Now, measurements from the Solar and Heliospheric Observatory (SOHO) satellite have provided the most detailed picture to date of these so-called minor elements, which carry major information about processes occurring in the sun's corona.

Antoinette B. Galvin of the University of Maryland in College Park presented data from the Charge, Element, and Isotope Analysis System (CELIAS), a group of instruments aboard SOHO that counts and evaluates particles in the solar wind.

Scientists recognized some of the chemical isotopes from previous satellite observations of the solar wind, but CELIAS also detected many that had not been reported there before. These include isotopes of silicon, sulfur, calcium, chromium, iron, and nickel. Isotopes of neon and argon were measured by SOHO but not by earlier satellites, although they had been detected in solar wind during the Apollo lunar landings more than 20 years ago, Galvin says. …