He pioneered many studies of the global solar structure, including large-scale solar phenomena such as magnetic sectors and polar magnetic regions. Working with Norman Ness, he discovered that during times of moderate solar activity, the interplanetary medium is ordered into the large-scale magnetic structures which he called sectors. Together with Robert Howard of Mount Wilson, he then showed that these structures could be mapped back onto the Sun.

John M. Wilcox was a graduate of Iowa State College (BS 1948) and the University of California at Berkeley (PhD 1954). He served in the U.S. Army Air Force during World War II. He was a physicist with the Lawrence Radiation Laboratory from 1951 to 1961. In 1961-62 he was a visiting physicist at the Royal Institute of Technology in Stockholm. Returning to the University of California, he was with the Space Sciences Laboratory from 1964 to 1971.

Wilcox developed many innovative techniques to extract signals from the variety of noisy data that often plague researchers in Solar Terrestrial physics. John had perception in attacking fruitful problems and the persistence to devote himself to difficult physical puzzles from which others might shy away. Over the past decade, he and his associates established the as-yet-unexplained connection between the sector boundaries of the interplanetary magnetic field and areas of strong vorticity at the lower boundary of the Earth's statosphere. The effect, though small and of variable magnitude, has been independently confirmed and may be of great importance in weather and climate models.

John Wilcox recognized the value of international cooperation and exchanges. He arranged extended visits to Stanford by researchers from many countries, including the USSR, China, Japan, England, France, Italy, Denmark, and Sweden. These collaborations led to exciting and enlightening cultural exchanges, as well as important scientific results. He also organized and participated in many national and internaltional scientific meetings, where he not only contributed his own exciting results, but engaged in discussions on the wide variety of subjects in which he maintained interest. He was active in meetings and symposia of the International Astronomical Union and the International Union of Geodesy and Geophysics. He also chaired the US participation in the US-USSR Bilateral Cooperation under Environmental Working Group VIII from 1973 to 1979. He was a Fellow of the American Association for the Advancement of Science, the Americal Physical Society, and The Royal Astronomical Society (London); and a member of the Americal Geophysical Union, the American Astronomical Society, the Astronomical Society of the Pacific, the International Astronomical Union, and the American Meteorological Society. He served on numerous advisory committees for solar physics, space science, and solar-terrestrial relations.

John was known to his scientific associates not only for his research accomplishments and stimulating ideas, but for his gentle manner of giving help to others. He was a talented clarinet player, and deeply loved chamber music. At home and wherever he travelled, he always made time for musical events.

John Marsh Wilcox died while swimming in the Sea of Cortez near Puerto Penasco, Mexico on 14 October 1983. He is survived by his wife Ann, daughter Sharon, and son David.

October 1983