Gerold Yonas

Electron beam focusing and application to pulsed fusion

This paper reviews recent work on the focusing of high-power relativistic electron beams in diodes and discusses concepts for pulsed fusion based on this technology. The physics of high-current relativistic electron beam focusing using plasmas in high-current diodes is studied experimentally and with computer simulation. The physics of the beam interaction with dense targets and the requirements for break-even are briefly discussed.

Intense Particle Beams

Substantial progress has been made recently in generation, focusing, and transport of intense electron and light ion beams. The impetus for this work has been to develop a 1 MJ, 1014W particle beam device for inertial confinement ignition experiments and to create a practical technology base for application to future commercial power reactors.

Advances in Inertial Confinement Fusion Research (Report on the IAEA Technical Committee Meeting, Kobe, 1983)

Nearly 70 participants from 12 countries (Argentina, Brazil, Canada, German Democratic Republic, Federal Republic of Germany, Italy, Israel, Poland, Sweden, Union of Soviet Socialist Republics, United States of America, and the host country Japan) met in Kobe at the IAEA Technical Committee Meeting on Advances in Inertial Confinement Fusion (ICF) Research from 14 to 17 November 1983. It was the fifth Technical Committee Meeting on ICF, the last having taken place in Osaka in 1979 (Nuclear Fusion 20 (1980) 507).

Electron-beam-induced pellet fusion

ConclusionAs we have seen, there are many problems which must be dealt with if we are to achieve successful pulsed fusion using electron beams. In order to accomplish this goal, there are three crital areas of physics which will require substantial clarification: (1). beam focusing in low-inductance diodes, (2) symmetric input to the target, and (3) energy deposition in the outer region of the pellet. The accelerators we now have and are planning to build in the near future should provide the needed basis of fundamental understanding. If beams can be focused efficiently down to the millimeter sizes at power levels of ∼ 1014 W, then extremely interesting implosion studies can be carried out. If these prove successful within the next several years, then we may be able to go onward toward producing prototype fusion reactors, and much later, if many technical problems are solved, practical fusion power may follow.

Expanding Human Cognition and Communication

In order to chart the most profitable future directions for societal transformation and corresponding scientific research, five multidisciplinary themes focused on major goals have been identified to fulfill the overall motivating vision of convergence described in the previous pages. The first, “Expanding Human Cognition and Communication,” is devoted to technological breakthroughs that have the potential to enhance individuals’ mental and interaction abilities. Throughout the twentieth century, a number of purely psychological techniques were offered for strengthening human character and personality, but evaluation research has generally failed to confirm the alleged benefits of these methods (Druckman and Bjork 1992; 1994). Today, there is good reason to believe that a combination of methods, drawing upon varied branches of converging science and technology, would be more effective than attempts that rely upon mental training alone.

Advances in ICF using light-ion beams

PBFA II, with parameters of 3.5 MJ and 100 TW, is being designed to allow inertial fusion ignition experiments using imploding foils or light ion beams. Flexibility is being retained to implode a cylindrical foil through magnetically insulated power concentration at 30 MA or to drive one or more ion diodes operating in the 6–30 MV range. In both cases our goal is to deliver 50 TW/cbdt and 1 MJ to a target in order to investigate ignition and possibly breakeven.

Technology of Inertial Confinement Systems (Report on the IAEA Advisory Group Meeting, Dubna, 1976)

The IAEA Advisory Group Meeting on the Technology of Inertial Confinement Experiments was held at the Joint Institute for Nuclear Research at Dubna, USSR, on 19–23 July 1976. The meeting reviewed progress and engineering problems of research on inertial confinement systems and discussed new conceptual designs of fusion reactors.

Progress and directions in inertial fusion

The Office of Inertial Fusion, in this panel discussion on progress in inertial fusion, says that their near-term objective in the program is to determine the requirements in driver energy and pellet design to ignite a small fusion pellet in the laboratory. The author feels that they have developed a basis that gives a good projection of what will be required. The Lawrence Livermore National Laboratory discusses a laser facility called NOVETTE. One of the interesting things about the technology is that the crystal arrays are relatively large. The University of Rochester discusses an area called direct drive. The Los Alamos National Laboratory comments on progress in the understanding of electromagentic wave and particle interactions. The Naval Research Laboratory reveals progress in producing a uniform illumination with a realistic laser. The Sandia National Laboratory discusses the production of very high-brightness beams at modest volatages.

Electron‐Beam‐Induced Fusion

The use of tightly focused relativistic electron beams has only recently been seriously considered as an alternative to lasers as a means of heating and compressing matter for achieving fusion. The potential attractiveness of this approach stems from the demonstrated high efficiency, intrinsic simplicity, and the ability to scale pulsed power and electron beam technology. In particular, the foundation has already been prepared to allow us to embark on the development of a 1013 W pulsed electron accelerator to deliver 105 J or more to a spherical target. Although such a device will in the future allow us to test more fully the feasibility of the concept, many of the fundamental questions related to the principles underlying this idea present exciting challenges to the physics community and can be tested with considerably smaller facilities. The important questions include the limitations of electron beam focusing, symmetry of irradiation of mm size pellets, and energy deposition. Vital tools in addressing ...