Professor Emeritus of Physics and Astronomy (UC Riverside)
R. Stephen White, a Distinguished Professor of Physics (now Physics and Astronomy) at UC Riverside until he retired in 1990, passed away peacefully on April 8, 2018 in Santa Barbara after a series of illnesses.
Steve joined the UCR physics faculty in 1967 and initiated the new astrophysics program. He was the founding Associate Director of the Institute of Geophysics and Planetary Physics (IGPP), serving in this position for 25 years, until 1992. His research had significant impacts in multiple areas, including nuclear physics, space physics, plasma physics and high-energy astrophysics. At UCR, he was a strong, tireless and well respected academic leader and educator, serving as the physics chairperson from 1970 to 1973.
Steve was born in Ellsworth, Kansas and attended Southwestern College in Winfield, Kansas, where he met his future wife of 71 years, Freda. After receiving a Bachelor of Arts degree in 1942, he went on to receive a Masters of Science degree in physics from the University of Illinois at Urbana-Champaign in 1943. He served as a Naval Officer at the Naval Research Laboratory helping to develop the thermal diffusion separation of uranium 235 from uranium 238 for the Manhattan Project. After WW II, he continued his graduate physics education at UC Berkeley, completing a Ph. D. in 1951 in the field that was then called “nuclear physics.”
With two colleagues, Steve was the first to study mesons produced by gamma rays at an accelerator. Research for his dissertation, “Photomesons from Deuterium,” was performed at the Lawrence Radiation Laboratory (now LBL) electron synchrotron, as part of the research program headed by his dissertation advisor Edwin M. McMillan, who shared the 1951 Nobel Prize in Chemistry with Glenn Seaborg for discovering Neptunium (atomic number 93). Here, Steve was introduced to the emerging technology of thick “nuclear emulsions” for detecting and tracking high energy charged elementary particles. He continued his research for the next 10 years at both LBL and the Lawrence Livermore National Laboratory (LLNL), heading up the Nuclear Emulsion Group at LLNL. While much of Steve’s research was classified during this period, there were opportunities for unclassified research as well.
In 1959, with Stanley C. Freden, they had an opportunity to fly small stacks of nuclear emulsions in Air force missile nose cones, which were recovered down range from Cape Kennedy after reaching an altitude of 1,200 km. Until that time, the identity of the magnetically trapped particles in the Van Allen radiation belts was unknown. Their results (Phys. Rev. Letters 3, 9-10, 1959) showed that the particles were overwhelmingly protons. In a long review article in Physics Today (Oct. 1966), Steve summarized our knowledge about “The Earth’s Radiation Belts”.
In 1961, Steve joined the technical staff at the Aerospace Corporation in El Segundo, CA, which was founded in 1960, and assembled and headed the “Particles and Fields Division.” Much of his research at Aerospace Corp. was classified. In 1967, UCR professor Walter H. Barkas recruited Steve to join the UCR physics faculty. Barkas had come to UCR in 1965 from LBL/UCB where he pioneered the use of nuclear emulsions. Realizing that this technique had limitations for high-energy astrophysics observations, Steve began to develop electronic instruments for use with large stratospheric scientific balloons that could carry large detectors to the upper reaches of the earth’s atmosphere. With a core group of graduate students and Office of Naval Research support, the “double scatter neutron” detector with time-of-flight was developed to directly measure the high-energy albedo neutrons leaving the top of the earth’s atmosphere that subsequently decayed into protons and electrons to populate the Van Allen Belts. With four balloon flights at different latitudes, these seminal observations measured the neutron energy, angular and altitude dependence (Phys. Rev. Letters 28, 982, 1972, JGR 79, 17-22, 1974). The parachute didn’t open at the termination of the last flight and the instrument was completely destroyed, but the telemetry data was received.
Steve realized that the double scatter technique for neutrons could also be used to make a gamma ray telescope. With this in mind, he began an entirely new research effort at UCR in gamma-ray astronomy. This led to several generations of balloon-borne medium energy (1-100 MeV) Compton gamma ray telescopes, and a wide range of important new results. These include:
1)The first detection of cosmic gamma ray bursts from a balloon instrument. These were first detected by US nuclear surveillance satellites in the 1960s and declassified in 1973.
2) Gamma ray flux upper limits for a number of important Active Galactic Nuclei.
3) Pulsed gamma rays from the Vela and Crab pulsars.
4) Co-56 gamma ray emission from Supernova 1987A. SN 1987A was the closest supernova to be observed in the last 400 years. Ni-56 is produced during the supernova explosion of a massive star and quickly decays to Co-56 and then to Fe-56 with a mean lifetime of 114 days. UCR’s observation was made 418 days after detonation from central Australia and helped determine the initial amount of Ni-56 that was produced. Steve also contributed an important book chapter entitled “Review of Gamma Rays from SN1987A” in 1991.
5)Gammaray emission from unshielded nuclear reactors on Soviet ocean reconnaissance satellites as they passed over the balloon telescope in central Australia. These gamma rays produced positrons on the surface of the satellites that became trapped and contaminated the Van Allen belts then annihilated, producing a 0.51 MeV gamma ray background that was harmful to astronomy observations at the energy. The DoD declassified the Soviet satellite information when Steve submitted the UCR results for publication.
Steve was elected a Fellow of the American Physical Society (APS) in 1969. In 1981, he was selected as the UCR Faculty Research Lecturer and was elected a Fellow of the American Association for the Advancement of Science (AAAS) in 1995. A total of 17 physics graduate students completed their Ph.D. dissertation under his guidance. He has held visiting research appointments at numerous institutions. These include the Max-Planck Institut fur Extraterrestrische Physik, Garching bei Munchen, the University of Nagoya, the Oak Ridge Associated Universities, the Cavendish Laboratory, University of Cambridge, and Los Alamos National Lab.
In 1970, he authored a comprehensive book titled “Space Physics.” This book included detailed reviews of the earth’s radiation belts as well as the earth’s atmosphere, ionosphere, magnetosphere, and Sun. After retiring to Santa Barbara in 1992, Steve began writing “Science Views” for the Santa Barbara News Press. The purpose was to furnish science information that the public may find useful in making difficult decisions. These more than 150 articles were collected and published in a single volume in 1998 called “Why Science.” Steve received the 2000 UCR Emeritus Faculty Research Award for this effort. Not stopping there and building on his vast quantitative physical science background, he authored a third book in 2005 titled “Energy for the Public.” The goal was to make “the case for increased nuclear fission energy” as one of the solutions to combat global warming.
Through his far-sightedness, indomitable spirit, perseverance, resolve and trustfulness, Steve was an internationally recognized authority in the fields of space physics and astrophysics. These qualities were also very evident in his academic service efforts and dedication to teaching at UCR. He will be remembered for being fearless when hard decisions needed to be made and a strong advocate for principles he believed to be correct.
His friends, students, and colleagues will always remember Steve for his devotion to his family. He was an accomplished runner, tennis player and gardener. He is predeceased by his loving wife Freda, children David and Lynn and his sister Nancy. His children Peggy and John, brothers Byron and Herbert, 7 grandchildren and 15 great-grandchildren will always lovingly remember him.