Artan Qerushi

Colliding beam fusion reactor space propulsion system

The Colliding Beam Fusion Reactor Space Propulsion System, CBFR‐SPS, is an aneutronic, magnetic‐field‐reversed configuration, fueled by an energetic‐ion mixture of hydrogen and boron11 (H‐B11). Particle confinement and transport in the CBFR‐SPS are classical, hence the system is scaleable. Fusion products are helium ions, α‐particles, expelled axially out of the system. α‐particles flowing in one direction are decelerated and their energy recovered to “power” the system; particles expelled in the opposite direction provide thrust. Since the fusion products are charged particles, the system does not require the use of a massive‐radiation shield. This paper describes a 100 MW CBFR‐SPS design, including estimates for the propulsion‐system parameters and masses. Specific emphasis is placed on the design of a closed‐cycle, Brayton‐heat engine, consisting of heat‐exchangers, turbo‐alternator, compressor, and finned radiators.

Classical transport in a field reversed configuration

The transport of charged particles in a field reversed configuration (FRC) was previously considered to be turbulent because it is much faster than classical predictions. Classical transport has mainly been developed for plasmas in which the gyroradii of particles are small compared to the scale lengths of the variation of the density and magnetic field. This assumption is quite inappropriate for an FRC where the magnetic field vanishes on a surface within the plasma. Classical theory has been extended to include large ion gyroradii. A classical loss-cone process is revealed that is consistent with the transport experiments in which the ion gyroradii were comparable in size to the plasma radius.

Hybrid magneto-hydrodynamic simulation of a driven FRC

We simulate a field-reversed configuration (FRC), produced by an “inductively driven” FRC experiment; comprised of a central-flux coil and exterior-limiter coil. To account for the plasma kinetic behavior, a standard 2-dimensional magneto-hydrodynamic code is modified to preserve the azimuthal, two-fluid behavior. Simulations are run for the FRCs full-time history, sufficient to include: acceleration, formation, current neutralization, compression, and decay. At start-up, a net ion current develops that modifies the applied-magnetic field forming closed-field lines and a region of null-magnetic field (i.e., a FRC). After closed-field lines form, ion-electron drag increases the electron current, canceling a portion of the ion current. The equilibrium is lost as the total current eventually dissipates. The time evolution and magnitudes of the computed current, ion-rotation velocity, and plasma temperature agree with the experiments, as do the rigid-rotor-like, radial-profiles for the density and axial-magnetic field [cf. Conti et al. Phys. Plasmas 21, 022511 (2014)].

Generation and transport of a low energy intense ion beam

This paper describes experiments on the formation and transport, in vacuum and plasma, of a low-energy (70-120 keV), high-intensity (10-30 A/cm/sup 2/), long-pulse (0.5-1/spl mu/s) H/sup +/ ion beam. The beam was generated in a magnetically insulated diode with an applied radial B-field and active hydrogen-puff plasma source at the anode. The combination of a ballistic focusing large area anode (250 cm/sup 2/) with a post-cathode toroidal magnetic lens and straight transport solenoid section provided beam transport to a distance of >1 m with an overall efficiency of /spl ges/ 50%. Two-dimensional single-particle computer simulations of the ions trajectory in the lens/solenoid system supported optimization of the lens and solenoid parameters.