The major contributions of space physics to fundamental physics and astrophysics are numerous. Well-known examples are magnetic reconnection, collisionless shocks, particle acceleration, nonlinear plasma physics, and coherent generation of radio waves. The space plasma group at CU are world leaders in research of these fundamental processes. Research involves satellite data analysis, numerical simulations, and analytical modeling in a variety of space and astrophysical plasma environments. The space plasma group includes:

The two classical particle acceleration mechanisms of astrophysics, Fermi acceleration and betatron acceleration, are active in the terrestrial magnetosphere, which is virtually the only region where in-situ measurements of particle acceleration can be made. The Earth's radiation belts and the reflected particles from the magnetosphere's bow shock are two important examples of these acceleration mechanisms. A third mechanism, discovered and studied by space physics satellites, involves electric fields that are parallel to the local magnetic field direction. These quasi-static, parallel electric fields, previously believed not possible in a collisionless plasma, appear to be supported by strongly nonlinear plasmas. Theories of such self-consistent fields and the associated particle acceleration are major topics in non-linear plasma research. The LASP space physics group has been a leader in particle acceleration research with theoretical advances and in-situ observations which may be relevant to particle acceleration in astrophysical sources such as pulsar magnetospheres, and to the galactic cosmic ray acceleration problem.

Magnetic reconnection is a universal plasma process which converts stored magnetic energy into kinetic and thermal energies. The reconnection process is initiated in a small region, but its consequences are global. Reconnection is believed to be a major contributor to the initiation of solar flares, a source for coronal heating, and a major solar magnetic flux loss process via coronal mass ejections. Similar processes may well operate in accretion disks. It is also known to be an important facilitator for the entry of solar wind plasma into the magnetosphere, and a release mechanism of stressed magnetic configuration in the magnetotail which leads to substorms. Magnetic reconnection is not only critical to magnetospheric processes, but in the Earth's magnetosphere is one of the few regions that one can establish definitive observations. LASP is advancing several missions that will study magnetic reconnection.

Perhaps the best known success of space physics is the discovery of collisionless shocks. Collisionless, fast mode shocks, decelerate and thermalize a supersonic plasma flow, accelerating a fraction of the incident particles to high energies. Shocks are a ubiquitous source of particle energization and are important in coronal, interplanetary, supernova remnant, and heliospheric contexts. Earth's bow shock is an ideal testbed for studying shock microphysics. LASP is advancing several missions that that will study collisionless shocks. Most astrophysical shocks are expected to be collisionless, so this research has broad relevance to astrophysics.

The nearby space environment is a unique laboratory in which to study nonlinear plasmas, including the processes mentioned above as well as beam-plasma interactions, double layers, turbulence, wave collapse, and kinetic nonlinearities. Ironically, the low densities in space plasmas are well suited to investigate plasma behavior to the smallest fundamental scales sizes (Debye length) which are very difficult to probe in laboratory plasmas. The small-scale nonlinear processes studied by space physicists are often the same as those addressed by the fusion and laboratory plasma community.

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