WHAT DID THE 2012 EARLY CAREER AWARD ALLOW YOU TO DO?
Lasers are everywhere in our everyday lives. We use them in bar code readers at the supermarket, in telecommunications equipment, and in medical devices. Since their invention in the 1960s, lasers have also been envisioned as a tool for high energy density physics. For example, lasers could accelerate particles in table-top-sized systems. These lasers could potentially replace several-mile long, ‘traditional’ accelerators by using plasma, i.e., ionized gas.
Early on, the pioneers of laser development had the vision that high-energy laser systems could compress tiny balls of hydrogen. This compression recreates conditions like those found in stars. The fusion reactions between light nuclei produce more energy than the laser originally contained. This so-called Inertial Confinement Fusion concept has recently been demonstrated at the National Ignition Facility at Lawrence Livermore National Laboratory.
However, details of how laser pulses interact with matter are often complicated and difficult to model on the computer. For instance, relevant length scales in laboratory experiments range from millimeters down to nanometers; this is the distance over which the charges in plasma can feel each other’s presence. That makes first-principle computer models extremely expensive.
The Early Career Award allowed me to study how intense, extremely short laser pulses interact with matter using computer simulations.
Within such pulses, the optical field oscillates only a few times. When the pulses strike the polished surface of a metal, the field accelerates electrons along the surface, launching a heat wave and a flood of electrons into the solid. This effect can be used to ‘explode’ nanostructured foams with extreme electromagnetic fields, creating a very dense, hot plasma.
My work has opened a new field of research. Now, we can study extreme nuclear physics reactions at rates many orders of magnitude higher than current accelerator experiments. Currently, I am focusing on energetic laser pulses that might one day play a role in igniting fusion capsules on the National Ignition Facility.
Andreas Kemp is a staff scientist at Lawrence Livermore National Laboratory
SUPPORTING THE DOE SC MISSION:
The Early Career Research Program provides financial support that is foundational to early career investigators, enabling them to define and direct independent research in areas important to DOE missions. The development of outstanding scientists and research leaders is of paramount importance to the Department of Energy Office of Science. By investing in the next generation of researchers, the Office of Science champions lifelong careers in discovery science.
For more information, please go to the Early Career Research Program.
A.J. Kemp and L. Divol, “What is the surface temperature of a solid irradiated by a petawatt laser?” Physics of Plasmas 23, 090703 (2016). [DOI: 10.1063/1.4963334]
A.J. Kemp, S.C. Wilks, E.P. Hartouni, and G. Grim, “Generating keV ion distributions for nuclear reactions at near solid-density using intense short-pulse lasers.” Nature Communications 10, 4156 (2019). [DOI:10.1038/s41467-019-12076-x]
A.J. Kemp and S.C. Wilks, “Direct electron acceleration in multi- kilojoule, multi-picosecond laser pulses.” Physics of Plasmas 27, 103106 (2020). [DOI:10.1063/5.0007159]
DOE Explains… offers straightforward explanations of key words and concepts in fundamental science. It also describes how these concepts apply to the work that the Department of Energy’s Office of Science conducts as it helps the United States excel in research across the scientific spectrum. For more information on nuclear fusion and DOE’s research in this area, visit “DOE Explains…Nuclear Fusion Reactions,” “DOE Explains…High Energy Density Plasmas,” and “DOE Explains…Burning Plasma.”
Additional profiles of the Early Career Research Program award recipients can be found at /science/listings/early-career-program.
The Office of Science is the single largest supporter of basic research in the physical sciences in the United States and is working to address some of the most pressing challenges of our time. For more information, please visit the Office of Science website.