Noah Hershkowitz

On 13 November 2020, the plasma-physics community lost distinguished scientist and teacher Noah Hershkowitz, Irving Langmuir Professor Emeritus of Engineering Physics at University Wisconsin–Madison (UW–Madison). Few have contributed so much broadly to field plasma science. Noah’s work was foundational in nature, but it profoundly influenced applications spanning gamut from materials processing fusion. He guided generations physicists, probed theories assumptions, provided international leadership community. founding editor 1992 Plasma Sources Science Technology, which has become premier venue for disseminating low-temperature Hershkowitz UNIVERSITY OF WISCONSIN–MADISONPPT|High-resolutionNoah born on 16 August 1941 Brooklyn, New York, attended High School Music Art. earned his bachelor’s degree Union College 1962. While taking an honors physics course there, he another student fabricated a working ruby laser only two years after first built. 24 when PhD Johns Hopkins University; under adviser J. C. Walker, worked experimental Mössbauer spectroscopy. After teaching university about year, joined department Iowa.Noah started out as nuclear physicist. However, fascination with 1971 colloquium electrostatic shocks laboratory plasmas motivated abrupt shift physics, despite never having taken single topic. thought would be fun. His beginning foray included study solitons double layers, results challenged conventional wisdom regarding those curious structures. always asked basic questions first—such as, How does potential get point A B?—to core underlying fundamental experiments led development refinement emissive probe techniques measuring space potentials. is now basis how measurements are made fields ranging Hall thrusters.While sabbatical 1980 Colorado Boulder, recruited take charge large-scale Phaedrus tandem-mirror fusion program UW–Madison, did later that same year. steered new direction. The conducted groundbreaking featured simplified axisymmetric coil set achieved magnetohydrodynamic stabilization through externally applied RF power, machine do so. Phaedrus-B device continue influence designs worldwide. also served many US Department Energy mirror committees, including US/Japan Joint Planning Committee tandem mirrors, 1989 key participant DOE Office Fusion Energy’s US/USSR exchange program.When focused efforts tokamak fusion-confinement concept late 1980s, built Phaedrus-T tokamak, began semiconductor manufacturing. pioneering research helped advance critical technology time responsible maintaining Moore’s law. plasma-etch group UW–Madison’s Center Aided Manufacturing over decade, center’s director more than decade that. characteristic integrity regain competitiveness microelectronics industry.Although thriving energy programs, let go pursued career. sorts held special him were assumptions dated back Langmuir’s 1920s had no definitive benchmark. advances probe- laser-based diagnostics allowed make seminal “sheath problem,” describes boundary layer mediating interaction between surfaces.Noah spent last half career wheelchair, dealing with, often just ignoring, primary progressive multiple sclerosis. ability undaunted by disease inspiration. brilliant kind generous mentor, cared enough create environment where everyone—a vast, diverse “everyone”—could thrive.“Physics like jigsaw puzzle that’s really old,” once said. “All pieces worn down. Their edges messed up. Some been put together wrong way. They sort fit, they’re not actually right places. game them way find world works.”Noah mourned physicists throughout world.© 2021 American Institute Physics.