Research

Here is a brief description of the two main research topics in the Bose group

Topic I :  Inertial Confinement Fusion (ICF)

In nuclear fusion, very high temperatures and pressures force atomic nuclei to overcome their mutual electrostatic repulsion and merge together, releasing energy. The inertial confinement fusion (ICF) approach, proposed in 1960 at Lawrence Livermore National Laboratory (LLNL), uses high-power lasers to heat a tiny, 1 mm diameter, spherical capsule filled with hydrogen gas to temperatures of the solar core (~100 million Kelvin) required for nuclear fusion. In 2009, the National Ignition Facility (NIF) laser was built to demonstrate ‘ignition’, i.e., produce a fusion trigger equivalent to the spark of a combustion engine that then burns the rest of the fuel. Recently, on Dec 5th, 2022, NIF achieved the ignition milestone. These experiments used 2.05MJ laser energy and produced 3MJ fusion energy output, with a net energy gain of 1.5x. This is the first demonstration of controlled laboratory fusion producing more energy output than used to heat the system; a breakthrough in fusion energy research. However, a commercially viable fusion power plant requires much higher gains of 100x, considering the wall plug efficiency of the lasers.

Magnetized Inertial Confinement Fusion

We conducted experiments where we added external magnetic fields to the ICF implosions to boost the fusion gain. The applied B-field can trap the charged plasma particles by making them gyrate around the field lines, thus suppressing heat losses and increasing the chances for fusion. We observed a reduction of heat losses due to magnetization at OMEGA [A. Bose et al., Phys. Rev. Lett. (2022)] and an increase the fusion gain at NIF [J. D. Moody et al., Phys. Rev. Lett. (2022)]. While we currently possess numerical tools to model the ICF implosion dynamics, we require the development of magneto-hydrodynamics (MHD) components to model and analyze the effect of adding the B-fields.

We are developing MHD simulation tools to model the applied magnetic fields in ICF implosions and study suppression of heat losses and quantitatively assess the increase in fusion gain. 

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Topic II :  High Energy Density Laboratory Astrophysics

Energetic laser systems [OMEGA, NIF] and pulsed-power drivers [Z-Facility] can create matter at extreme conditions that was previously inaccessible in the laboratory. This opens up new opportunities for discoveries by probing plasmas at high energy density with pressures ranging from 1 Mbar, the pressure at the center of the earth is 3.6 Mbar, to 100s of Gbar, 265 Gbar is the pressure in the sun’s core. In this research, we re-create a wide range of astrophysics phenomenon in the laboratory at much smaller scales to unravel the intricate physics mechanisms at play, and then apply these results to improve our understanding of the processes throughout the universe. For example, magnetic reconnection, a commonly occurring phenomenon in the universe and a key mechanism behind solar flares, was created in experiments leading to important understanding of the process [C.K. Li et al., W. Fox et al., G. Fiksel et al., M. Rosenberg et al.].  Turbulent dynamo, a phenomenon occurring in myriads of astrophysical processes: supernova explosions, galaxy cluster mergers, stellar outflows, etc., was recreated in terrestrial experiments to investigate the origin and amplification of magnetic fields in the universe [P. Tzeferacos et al., T.G. White et al.]. Experiments at Sandia’s Z facility provided vital measurements of iron opacity at solar interior temperatures [J.E. Bailey et al.] necessary for determining the internal temperature profile within stars [T. Nagayama et al.]. Currently experiments have explored only the tip of the iceberg of problems that can be studied at these systems. Enhanced capability to impose strong magnetic fields has created tremendous opportunities to engage with the space plasma and astrophysics groups at UD.

Laboratory astrophysics experiment is a young but rapidly developing research field, which studies astrophysical phenomena by using laser-produced plasma. Facilities like the OMEGA laser at the Laboratory for Laser Energetics at the University of Rochester can focus up to 30 kJ of energy onto a target that is less than 1 mm diameter for 1 ns, to recreate scaled astrophysical phenomena, such as supernova ejecta, bow shocks and magnetic reconnection. A broad range of plasma conditions, magnetic field configurations, and spatial and temporal scales are covered in these astrophysical systems.  The plasma parameters are scalable to develop astrophysical models in laboratory experiments, which supply an effective approach to understand the underlying mechanisms of some astrophysical observation results.

Magnetized Plasma Jet Collimation

Magnetic fields could be applied in laboratory environments, which plays an important role in producing magnetized plasma jets. In the past 10 years, unusual dynamics, especially the collimated structure exhibited by magnetized plasma jets, were studied in laboratory astrophysics experiments, which are universally observed on galactic and stellar scales. The experiment on the OMEGA laser facility and MHD simulations using FLASH code are designed for understanding the collimation mechanism of magnetized jets.