International Conference on Plasma Sciences

RODNEY J. MASON

Rodney Mason retired from the Los Alamos National Laboratory in Dec. 2005. Thereafter, he founded the Research Applications Corporation which received SBIR Grants for Plasma Code development from 2008-2013. Most recently Rod works through R_Mason Consulting. Rod received his Bachelors in Physics with honors from Cornell University in 1960 and his PhD from the Cornell Aerospace Engineering Department in 1964. He received a Fulbright Grant to study plasma physics1964-65 in Garching near Munich, W. Germany. In 1965-67 he served as an Asst. Prof. and Ford Postdoctoral Fellow in the Aeronautics and Astronautics Dept. at MIT. He was a Scientist Astronaut Finalist in 1967. From 1967-72 he worked at Bell Labs, Whippany with Norman Zabusky, studying High Altitude Effects. From 1972-2005 he worked at the Los Alamos Lab., mostly studying Laser Fusion and pulsed power electron dynamics. He received a distinguished performance award at Los Alamos in 1981. Rod became a Fellow of the APS in 1983, pursuant to his work on the Implicit Moment Method of simulation. He became an IEEE Senior Member in 1985 and is now an IEEE Life Member. Rod spent 1990-91 on sabbatical at Cornell University with David Hammer and Ravi Sudan. He received a Distinguished Achievement Award in Physics & Space Technology from the Lawrence Livermore Laboratory in 1994. Rod served as a Deputy Group Leader at Los Alamos in 2002, and developed implicit plasma codes under the laboratories LDRD program during 2004-05. After his retirement he spent Jan.-March 2006 at the Institute for Laser Energetics in Osaka, Japan. From 2007-13 at his Research Applications Corporation Rod built and distributed the 2D implicit plasma simulation code EPLAS. Dr. Mason has coauthored 102 papers and given or contributed to 277 formal talks.

Collisionless Shocks, Implicit Moments and Laser Fusion Implosions

As this year’s Charles. K. Birdsall Award speaker, I will focus on technical challenges that have highlighted my career since 1964. In my earliest days, I studied kinetic effects in sound propagation. Particles can run ahead of fluid waves, sending forth a precursor signal. Later, I studied high altitude explosions in the earth’s ionosphere that could lead to ion-acoustic, and magneto-sonic plasma shocks controlled by the earth’s magnetic field. In 1972 thermonuclear breakeven with laser fusion seemed an imminent possibility – 8 years away. At Los Alamos I co-authored the first PRL on DT micro-balloon implosions driven by sharply rising laser pulses. Longer wavelength laser beams (10.6) were found to produce copious hot electrons, drastically reducing implosion efficiency, and were then modeled by slow, explicit PIC codes. In 1981 with the new Implicit Moment Method I found that a co-set of fluid equations could be solved implicitly to generally predict net electron behavior using a time step far exceeding the electron Courant Condition. This greatly facilitated 2D studies of hot electrons, previously impeding straight-forward laser target implosions. In the later 80s the Sandia Laboratory and the Naval Research Laboratory were considering pulse power systems to implode targets. Energy flow to these targets was controlled by Plasma Opening Switches. We found that the Implicit Moment Method greatly facilitated the modeling of these switches. In the 90s we returned to making comprehensive studies of ICF target behavior with Los Alamos and Livermore target codes, supplemented by Implicit Moment hot electron modeling. Although I retired from Los Alamos in late 2005, I continued to explore implicit and ICF modeling issues, showing with coworkers in 2014 - at our Research Applications Corporation - that kinetics could be used to improve shock-viscosity modeling in ICF codes.