Dr. Debra (Debbie) Callahan is the co-lead for IFE Science at Focused Energy Inc. She joined Focused Energy after 35 years at Lawrence Livermore National Laboratory as a physicist and associate division leader. She was part of the scientific leadership of the team that achieved ignition on the National Ignition Facility (NIF) Laser.  She joined Focused Energy in 2022 to take the results from NIF and work toward developing inertial fusion as a source of clean energy.

Dr. Callahan is a Fellow of the American Physical Society Division of Plasma Physics and has been a co-recipient of the Dawson Award for Excellence in Plasma Physics twice (2012 and 2022). She has been recognized for her work on NIF by a Fusion Power Associates leadership award, the Ronald C. Davidson award, and the E. Gail de Planque medal.

Abstract: Using a laser to produce energy from fusion has been a grand challenge since shortly after the laser was invented.    Historic advances in inertial fusion have been made in the past few years on the National Ignition Facility (NIF) laser.   First was a “burning plasma” – where the plasma heating by fusion alpha particle deposition became the dominant source of heating.  Shortly after, the first experiment to achieve ignition, defined by the Lawson criterion, occurred.  This experiment demonstrated the first plasma where alpha heating dominated over all loss mechanisms, producing strong heating of the plasma, and fusion “gain” (energy out divided by laser energy in) of 0.72.   Lastly, fusion gain greater than 1 was achieved – fusion energy out more than 1.5x the laser energy put into the target.

The next grand challenge is to take the results from NIF to build a fusion power plant.  For a power plant, target gain of ~ 100 is needed and the design needs to be robust and reliable. In addition, targets need to be produced and fielded at high repetition rate (~ 10 Hz) but with low cost and the laser needs to be efficient.  Finally, a reactor chamber needs to be able to capture the fusion neutrons to produce electricity as well as breeding tritium fuel for future targets.

In this talk, we will discuss path to ignition on NIF, lesson’s learned from NIF, and how we will use those to design and build a fusion pilot plant.

Prof. Dr. Thomas Klinger, studied physics at the Christian-Albrechts University of Kiel. After a research period in France he obtained his PhD in 1994 with a thesis on non-linear plasma dynamics. As a research assistant at the University of Kiel, Klinger was concerned with drift wave turbulence and nonlinear plasma structures. As visiting scientist, he conducted research at the Alfvén Laboratory in Stockholm, the Centre de Physique Théorique and the Université Aix-Provence in Marseille and Max-Planck-Institute of Plasma Physics in Garching. He obtained his habilitation in 1998 with a thesis on the control of plasma instabilities. Shortly thereafter he was appointed Professor of Experimental Physics at the University of Greifswald, where he has headed the Institute of Physics as chair from 2000 till 2001. He is head of the "Stellarator Dynamics and Transport" Division and since 2005 scientific director of the project Wendelstein 7-X.

Abstract: Magnetically confined plasmas provide the most advanced approach towards nuclear fusion energy on earth. The basis of the two leading concepts, tokamaks and stellarators, is a strong toroidal magnetic field combined with a poloidal magnetic field to obtain twisted field lines (rotational transform). The main difference between the two is that stellarators create the poloidal magnetic field with external coils only and thus do not require a strong electric current in the plasma. During the development of stellarators it has turned out, however, that careful optimization of the magnetic field configuration is mandatory to achieve the required quality of magnetic confinement. 

The fusion research device Wendelstein 7-X is a large (30 m3 plasma volume) optimized stellarator with superconducting NbTi coils that create low-shear magnetic field with a rotational transform between 5/6 and 5/4 and 2.5 T on the magnetic axis. The mission of Wendelstein 7-X is to achieve a consolidated level of physics and technical understanding, with the aim to pave the way to steady-state fusion reactors based on the optimized stellarator concept. The stellarator fusion reactor requires plasma parameters as 2-31020 m-3 plasma density, 10-15 keV ion temperature and 2-3 s energy confinement time.

This paper reports on results from the recent long-pulse and high-performance plasma operation runs of Wendelstein 7-X with up to 2 MJ heating energy injected. The three key sectors of research are the following: (1) high plasma heating performance with both 140 GHz gyrotrons and 50 keV hydrogen neutral beam injectors, (2) controlled heat and particle exhaust with the water-cooled, actively pumped divertor using the magnetic island structure at the plasma edge, (3) high-performance plasma scenarios (1020m-3 plasma density at 3 keV ion temperature) achieved with suitable levels of plasma turbulence for controlled radial heat and particle transport. The main challenge is to find plasma scenarios consistent simultaneously with all three sectors under stable steady-state conditions.

Dr Simon Bott-Suzuki earned an M.Sc. in Chemical Physics and then a Ph.D. in Plasma Physics from the University of Sheffield in 1999 and 2004 respectively. His Ph.D. thesis concerned the experimental analysis and improvement of electrode emitter materials in deuterium lamps. He moved to Imperial College as a post-doctoral researcher in 2004 to work on experimental high energy density physics driven by pulsed power systems.

Dr Bott-Suzuki has been a Research Scientist in the Center for Energy Research University of California since 2006, and leads the Pulsed Plasma Physics group. His research encompasses magnetically driven plasmas for inertial fusion, laboratory astrophysics and basics plasma physics. Dr. Bott-Suzuki is a past Chair of the International Conference on Dense Z-Pinches (DZP 2014) and has supported the DZP and ICOPS conference series in various roles. He currently serves as a Guest Editor for IEEE Transactions on Plasma Science.

Abstract: High energy density physics research has focused on examining new frontiers of plasma behavior in the extreme conditions found in fusion plasmas and astrophysical systems amongst others. This has increasingly necessitated the use of large-scale experimental facilities to achieve such conditions, which are typically located at national laboratories. During a highly producing couple of decades significant advances have been made in inertial fusion performance, including achieving ignition at NIF, powerful x-ray sources for astrophysics studies, and contributions to basic science issues. A great deal of this progress has been based on physics scaling studies, novel experimental and numerical research, and diagnostic development carried out at university-scale. University research groups are vital to providing ideas, capabilities and personnel on which our achievements have been built.

In this talk, we will review some of the most significant program successes in HEDP science, with a focus on pulsed power research, and highlight how university-scale programs have been a fundamental part of progress. Contributions have comprised those from both large collaboratives, such as the NNSA Centers of Excellence, and innovative single PI programs. Pulsed power drivers from 10s of kilo-amperes to a few mega-amperes housed on campuses provide flexible platforms to test and develop new ideas, allowing students to test, fail and improve at their studies. Small experimental programs with extensive diagnostic access are readily combined with well-benchmarked simulations to work on specific issues, which then contribute to the larger picture. Many of these novel ideas, and indeed staff and students, end up at national programs, and it is this symbiosis which drives innovation and progress. We will conclude by taking as a collaborative case-study the development of one of the most promising approaches to inertial fusion energy; the MagLIF program at Sandia National Laboratories.