Accretion, Magnetohydrodynamics, Multi-dimensional Radiation-hydrodynamics, Plasmas, Star Formation, Supernova Remnants.
Klein has pioneered methods of radiative transfer and adaptive mesh refinement applied to computational astrophysics over the last several decades with particular application to star formation. He played a central role in the development of the radiation-driven implosion model for induced star formation and in developing the leading theory of stellar winds for hot stars. He founded the Berkeley Astrophysical Fluid Dynamics group with Chris McKee. He also leads a research group in developing scaled laboratory laser astrophysical experiments.
My research interests involve understanding the role of coupled radiation-gas dynamical flows in a wide range of astrophysical phenomena using extreme high resolution simulations with Adaptive Mesh Refinement (AMR). In the area of the dynamics of the interstellar medium, these include investigations into various aspects of triggering star formation by ionization-shock fronts in molecular clouds, the interactions of supernova shock waves with clouds in the interstellar medium, and cloud-cloud hydrodynamic collisions. In the area of star formation, I am applying the state-of-the-art parallel AMR magneto-radiation-hydrodynamics code ORION that I have developed with Chris McKee to study the gravitational collapse and fragmentation of turbulent molecular clouds leading to the formation of molecular cores and stars and to the formation of stellar clusters. I am studying the formation mechanisms of both low mass stars and the formation of massive stars including feedback mechanisms such as radiation and protostellar winds. I am also studying non-ideal MHD turbulence and its role in star formation. Additionally, I investigate both collisionless and collisional astrophysical phenomena by doing scaled astrophysical experiments on state of the art laser platforms.