Distinguished Lecturer in Plasma Physics

Note: The 2020 Distinguished Lectures in Plasma Physics will be remote presentations.

Want to learn more about fusion energy and plasma science? Invite an expert to give a talk at your institution!

The goal of this program is to share recent advances in fusion energy and plasma science with the larger scientific community, particularly with academic institutions that may not have a plasma physics program. Lectures are often given at department colloquium or as an evening public lecture. 

The DPP Lecturers are available (for free!) to give talks at U.S. colleges and universities for the academic year. Expenses are covered under the Plasma Physics Travel Grant Program funded by the U.S. Department of Energy. No travel-related expenditure is expected from the lecture-hosting institution.

The Lecturers may be invited by clicking on the links below. Interested in nominating yourself or someone else as an APS-DPP Distinguished Lecturer? Apply here. 
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2020 Distinguished Lecturers

Lasers, Plasmas, and the Big Things We Could Do If We Had Small Accelerators

Wim Leemans, Director, Accelerator Technology and Applied Physics Division and Berkeley Lab Laser Accelerator Center

One of the things that immediately impresses people about particle accelerators is how big they are. Plasma physics and laser technology could make them much, much smaller. Accelerators have become a vital part of the infrastructure of discovery science and also have a broad range of societally and commercially crucial applications in industry, security, energy, the environment and medicine. For many applications, the size, cost, and non-portability of accelerators are limiting factors that can lead to missed opportunities. In a new generation of accelerators, charged particles “surf” on a wakefield created as an intense laser (or, in some designs, a driving particle beam) passes through a plasma, displacing the electrons there. The resulting electric field gradient can be up to a thousand times as intense (tens of gigavolts per meter) as that in a conventional linear accelerator based on radiofrequency power and sizable resonant cavities. Because the electric field—the actual mechanism of acceleration in a linac—is so much stronger, these accelerators can reach energy levels in a few inches that would conventionally require machines as long as a football field. For instance, the Berkeley Lab Laser Accelerator (BELLA) Center has accelerated electrons to 4.2 GeV in a 9 cm plasma channel. Although many challenges remain, this new technology is at the brink of offering a profoundly different way to build particle accelerators with the promise of being vastly smaller and cheaper than today’s. That would open up new opportunities to deploy accelerators for discovery science, and applications, including ones where instead of bringing the problem to a national laboratory or other large central facility, we must bring the accelerator to the problem. While our ultimate goal is a high-energy physics collider, we are also exploring radiation sources such as free electron lasers and even an arthroscopic laser-plasma accelerator small enough to put into the site of a cancer, attacking it directly to minimize side effects. In this talk, we will discuss the physics principles of the laser plasma accelerator, the challenges and next steps as we push toward 10 GeV and beyond in multistage systems, and the wide range of spinoff applications that are already being developed.

Extreme Environments at the World’s Most Powerful Pulsed X-ray Sources

Christine Coverdale, Sandia National Laboratories

The powerful x-ray outputs produced by pulsed power devices at Sandia National Laboratories provide unique opportunities to study a wide range of physics, including high energy density plasmas, opacity, material properties, radiation effects, and inertial confinement fusion. The Z accelerator is the world’s most powerful source of soft x-rays and can provide upwards of 300 TW from a z-pinch load. Recent work at Z has resulted in the production of unprecedented outputs of 10-30 keV x-rays from pulsed power drivers. Higher energy photons are available at the Saturn accelerator, which utilizes diodes to produce bremsstrahlung x-rays >100 keV, and the Hermes III accelerator, which is the world’s most powerful gamma-ray generator. Efforts are currently underway to improve these sources and develop a path to high-yield fusion sources, which would increase the x-ray outputs further, and provide neutron capabilities. This presentation will review the current state of x-ray sources at the Sandia pulsed power facilities, discuss future facility capabilities, and highlight several of the research activities that utilize these facilities, including z-pinch physics and studies of systems and materials in extraordinarily intense radiation environments.

Fast Magnetic-Reconnection in Laboratory and Space Plasmas

Amitava Bhattacharjee, Princeton Plasma Physics Laboratory, Princeton University

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In recent years, new developments in reconnection theory have challenged classical nonlinear magnetic-reconnection models. One of these developments is the socalled plasmoid instability of thin current sheets that grows at super-Alfvenic growth rates. Within the resistive MHD model, this instability alters qualitatively the predictions of the Sweet-Parker model, leading to a new nonlinear regime of fast reconnection in which the reconnection rate itself becomes independent of S. This regime has also been seen in Hall MHD as well as fully kinetic simulations, and thus appears to be a universal feature of thin current sheet dynamics, including applications to reconnection forced by the solar wind in the heliosphere and spontaneously unstable sawtooth oscillations in tokamaks. In three dimensions, the instability produces self-generated and strongly anisotropic turbulence in which the reconnection rate for the mean-fields remain approximately at the two-dimensional value, but the energy spectra deviate significantly from anisotropic strong MHD turbulence phenomenology. A new phase diagram of fast reconnection has been proposed guiding the design of future laboratory experiments in magnetically confined and high-energy-density plasmas, and have important implications for explorations of the reconnection layer in the recently launched NASA MMS mission.

Guidance and Control of Fusion Energy Reactors of the Future

Gary Staebler, General Atomics

Fusion Energy, released by fusing hydrogen into helium, has the potential to provide carbon-free base-load electricity without the uranium waste of fission energy or the intermittency of solar and wind energy. Fusion is the source of the sun's heat and requires a high gas temperature like in the sun to initiate and sustain the fusion reaction. This talk will explain how ionized gas, known as plasma, that is hot enough to produce the fusion reaction, can be modeled, confined, guided, and controlled in present-day closed magnetic field plasma-confinement devices and in future fusion energy reactors. Continuing improvements in the predictive capability of theory models, thanks to validation efforts involving detailed experimental measurements, make it possible to predict the fusion energy production of the first international experimental reactor, scheduled to begin operation in 2025. Theoretical models, ranging from high fidelity numerical simulation of plasma turbulence, to reduced models that have been calibrated to the high-fidelity simulations, have enabled large experimental data-set validation of the theory. Artificial intelligence networks trained to learn these theoretical models make real-time guidance and control of the fusion reactors of the future possible.

The High-Field-Tokamak Path to Fusion Energy: Alcator to SPARC to ARC†

Earl Marmar, Plasma Science and Fusion Center, Massachusetts Institute of Technology

This presentation will review the physics and technology basis of a path to realizing fusion energy using the compact, high-magnetic-field tokamak approach. Innovations underway include increasing energy and particle confinement; improving transport barriers; maximizing the functionality of heating and current drive; effectively exhausting the extreme heat and particle fluxes in the boundary plasma; and controlling and optimizing (1) fusion-output-power handling, (2) the removal of helium ash from cooled alpha particles, and (3) non-hydrogen/non-helium impurities. With conservative assumptions about energy confinement, a pre-conceptual design has been developed for a net energy gain facility, SPARC (major radius R=1.65m, toroidal magnetic field BT=12T), using hightemperature, high-critical-magnetic-field superconducting magnets. Extrapolation to a larger, slightly lower-field (R=3.3m, BT =9.2T), steady-state pilot plant design, ARC [1,2], is projected to produce 500 MW of fusion power and would put a new electricity source on the grid. The extrapolations to SPARC and ARC rely heavily on the high-field results from Alcator C-Mod. Possible technology advantages of the high-temperature superconductors, including development of jointed coils for configuration flexibility and facility maintainability, will also be discussed. 

[1] B.N. Sorbom, et al., Fus. Eng. Des. 100(2015)378.

[2] A.Q. Kuang, et al., Fus. Eng. Des. (2019) in press.

†This work supported by US DOE and Commonwealth Fusion Systems.

Lightning in a Canteen: The Promise of Plasma-Treated Refreshment for Survival

John Foster, University of Michigan

An emerging health problem is water contamination of our freshwater supplies, from waste derived from pharmaceuticals, personal care products, and industry. Health impacts to the public and aquatic life range from endocrine disruption to cancer. Advanced water purification treatment of both domestic drinking water and treated waste water is needed because conventional water treatment methods are inadequate for the increasing trace amounts of these contaminants and because the resiliency of domestic water supplies against issues such as drought and infrastructure failure need to be improved. "Advanced oxidation", which introduces reactive oxygen species (ROS), such as ozone, hydrogen peroxide and hydroxyls, for degrading contaminants into harmless byproducts by a process known as mineralization, is a conventional solution but requires non-water consumables, i.e., chemicals. In contrast, introducing "plasma" to interact with the problem water can drive advanced oxidation without the need for non-water consumables and can be tailored to address a wide range of contaminants. In this talk, we review the threats to freshwater supplies, the shortcomings of conventional methods, and the promising solution posed by the interaction of plasma with water. Anecdotal cases of the effectiveness of this fascinating and effective approach to water treatment will be presented.

Stormy (Space) Weather: An EMFISIS on the Radiation Belt Storm Probes

Craig Kletzing, The University of Iowa

The NASA Van Allen Probes mission was launched in August of 2012 to investigate the dynamic environment of the Earth's radiation belts. The NASA twin satellite mission is flying through the Van Allen belts more than 50 years after their discovery with the most comprehensive set of instruments ever deployed in this region of space. Thought for many years to be an essentially solved problem in space plasma physics, the new measurements show that quite to the contrary, the radiation belts are a highly variable part of space that still holds many questions for active research. This talk will present the story of the evolution from mundane to hot research topic, some basics of radiation belt plasma physics, the cast of characters from killer electrons to whistler waves, and an overview of some of the most exciting results from the Van Allen Probes mission and, in particular, plasma wave results from the Electric and Magnetic Field Instrument Suite and Integrated Science (EMFISIS).

Making a Stronger Magnetic Bottle to Hold a Hot Fusion Plasma

Richard Buttery, General Atomics

A magnetic bottle is the next best thing to a star to contain a hot gas at the incredibly high temperatures and densities needed for its ions to collide frequently and fuse together, releasing energy. Higher temperature increases fusion probability while higher density raises collision frequency. The front-runner concept to achieve this uses a donut of very hot ionized gas (a ‘plasma’) held together by a loop of magnetic field – a toroidal confinement machine, or ‘tokamak’ from the original Russian. This magnetic field loop traps the ions and injected heat in the donut to reach temperatures ten times hotter than the core of the sun! Current also flows around the donut, enabling the structure to be shaped by further magnetic fields. This injects a twist in the magnetic field that shears apart turbulent eddies that would otherwise carry heat out of the core. Shaping and stretching the plasma, or driving this current closer to the surface of the donut increases this magnetic shearing, further inhibiting turbulent heat losses. It also helps couple the plasma magnetically to the conducting walls of the device to provide rigidity to large scale distortions. This allows very high pressures to be supported, at which point the ion orbits naturally generate their own ‘bootstrap’ current to sustain the configuration self-consistently. This “Advanced Tokamak” approach allows a self-sustaining fusion reactor to be conceived at a compact scale. These underlying principles, the stimulating science, engineering highlights, and the consequent path to fusion energy will be described.