The University of Arizona

J.R. Jokipii Elected to National Academy of Sciences

By Lori Stiles, May 2, 2001

University of Arizona Regents' Professor J. Randolph Jokipii of the Lunar and Planetary Laboratory has been elected to the National Academy of Sciences, one of the most prestigious honors in American science.

The Academy, chartered in 1863 by President Abraham Lincoln to guide public action in science, yesterday elected 72 new members and 15 foreign associates from 10 countries in recognition of their distinguished and continuing achievements in original research.

Jokipii said he learned of his election while at breakfast with his wife yesterday in a 6 a.m. phone call from Washington, D.C.

"I'm pretty happy," Jokipii said. "For me, this is right up there with the Regents' Professorship."

Regents' Professor Donald Hunten, also of the UA Lunar and Planetary Lab, was among the half-dozen NAS members at the Capitol to congratulate Jokipii over the phone. Jokipii joins Hunten as a member of the NAS geophysics section.

Rice University Provost Gene Levy said, "Randy has been the most sustained, focused and creatively productive researcher in the field of theoretical cosmic ray physics in the world in the past 30 years. This is clearly the basis for his richly deserved election to the Academy." Levy, former dean of the UA College of Science, collaborated with Jokipii on cosmic ray research at UA from 1974-1980.

Jokipii's work in theoretical and space physics covers many areas primarily related to the transport and acceleration of cosmic rays and energetic particles in the solar wind and in the galaxy.

A consistent focus of his research has been on the effect of the sun's magnetic field and the solar wind on galactic cosmic rays. The sun's magnetic field, which dominates the environment of our solar system out to 100 AU (100 times the distance between Earth and the sun), deflects incoming galactic cosmic rays.

Scientists have long known that this "solar modulation of cosmic rays" varies with the sunspot cycle.

Jokipii played a fundamental role in developing theory that explains how the solar wind and the solar magnetic field inhibit cosmic ray entry into the solar system. His work has proved what 25 years ago was Levy's and his heretical suggestion - that the polarity of the sun's magnetic field affects how the sun modulates the cosmic rays bombarding our solar system.

"Jokipii developed the accepted theory for the variation of cosmic rays in the heliosphere as determined by the solar cycle," said UA planetary sciences Professor Bill Hubbard. "It's a fairly arcane theory not easily explained, but the upshot is that it has predicted things that have been observed by spacecraft.

"While what Randy does is not exactly what I do, I've written some papers with him. It was a stimulating experience. I immediately knew I was working with a very smart man," Hubbard added.

Jokipii was an interdisciplinary scientist on the joint European Space Agency/NASA Ulysses mission launched to the sun in 1992. He and his team interpret Ulysses spacecraft observations made at the sun's poles in developing their theoretical models. Ulysses made a first-ever polar pass of the sun, over the south pole, in 1995, and a year later, a pass of the north solar pole. This period was one of low sun spot activity. After a gravity-assist swing around Jupiter, Ulysses is again poised for solar passes - this time during high sun spot activity.

Jokipii and his group are also guest investigators on NASA's ACE mission, the Anomalous and Composition Explorer spacecraft. Launched in 1997, ACE sits at the "L-1" point between Earth and sun where it measures cosmic rays.

A native of Michigan, Jokipii earned an undergraduate degree from the University of Michigan and, in 1965, his doctorate from the California Institute of Technology. His doctoral dissertation concerned the solar wind and energetic particles. He joined the University of Arizona faculty in 1974.

Jokipii is a Fellow of the American Geophysical Union and a Fellow of the American Physical Society. Other memberships and committee positions include the International Astronomical Union, International Academy of Astronautics, NASA Space Physics Committee and the Academy of Science Ad Hoc Cosmic Ray Physics Committee.

Those elected yesterday bring the total number of active NAS members to 1,874.
Academy members at the University of Arizona are:

Herbert E. Carter - biochemistry - 1953
Willis E. Lamb Jr. - physics - 1954
Frank J. Low - astronomy - 1974
William R. Sears - aerospace and mechanical engineering - 1974
Edward A. Boyse - microbiology and immunology - 1979
Donald M. Hunten - planetary sciences, Lunar and Planetary Lab - 1981
W. David Arnett - astronomy and physics - 1985
Robert E. Dickinson - atmospheric sciences, hydrology and dendrochronology - 1988
C. Vance Haynes - anthropology and geosciences - 1990
William R. Dickinson - geosciences - 1992
John H. Law - biochemistry and entomology - 1992
William S. Bowers - entomology -1994
Vernon L. Smith - economics - 1995
Margaret G. Kidwell - ecology and evolutionary biology - 1996
Brian A. Larkins - plant sciences, molecular and cellular biology -1996
J. Roger P. Angel - astronomy and optical sciences - 2000
J. Randolph Jokipii - planetary sciences, Lunar and Planetary Lab- 2001