Physics Colloquium - Magnetic Fusion Energy: Progress and Challenges

After the realization in the mid-1900s that thermonuclear fusion reactions, the process that powers the sun, could be controlled on earth, research programs to harness fusion as an energy source developed rapidly worldwide. Fusion potentially provides a large-scale energy source without the negative environmental impact of present fossil fuel and nuclear energy. For instance, coupled with the use of renewable energy sources and conservation, fusion could contribute to an energy economy that minimizes global warming. Experiments to control fusion have followed several lines, with recent breakthroughs in both inertial and magnetic confinement approaches. Inertial confinement experiments recently resulted in transient ignition of a fuel pellet. Magnetic confinement fusion devices (tokamaks) have provided significant levels of sustained fusion power. These experiments have operated in parameter regimes similar to those proposed for fusion reactors, giving insights into the important physics that control the plasma stability and confinement properties in these regimes. This talk will present an overview of the basics of fusion, the history and approaches to developing and harnessing fusion energy, and an insight into the physics understanding that is necessary for optimizing performance in tokamaks.