Optimization of ion flow rates in a helicon injected IEC fusion system
- Aeronautics and Aerospace Open Access Journal
Qiheng Cai, George H Miley
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The Helicon Injected Inertial Electrostatic Confinement (IEC) offers an attractive D-D neutron source for neutron commercial and homeland security activation neutron analysis. Designs with multiple injectors also provide a potential route to an attractive small fusion reactor. Use of such a reactor has also been studied for deep space propulsion. In addition, a non-fusion design been studied for use as an electric thruster for near-term space applications. The Helicon Inertial Plasma Electrostatic Rocket (HIIPER) is an advanced space plasma thruster coupling the helicon and a modified IEC. A key aspect for all of these systems is to develop efficient coupling between the Helicon plasma injector and the IEC. This issue is under study and will be described in this presentation. To analyze the coupling efficiency, ion flow rates (which indicate how many ions exit the helicon and enter the IEC device per second) are investigated by a global model. In this simulation particle rate and power balance equations are solved to investigate the time evolution of electron density, neutral density and electron temperature in the helicon tube. In addition to the Helicon geometry and RF field design, the use of a potential bias plate at the gas inlet of the Helicon is considered. Biasing the plasma potential can increase the downstream ion velocity, but the optimal bias is a complex function of the Helicon parameters. In general, the results indicate that ion flow rate could be optimized by increasing the power supply, properly modifying the helicon tube length, radius and bias plate voltage. The selection of helicon configuration parameters, including power supply, helicon tube length, radius and bias voltage to optimize ion flow rates in a steady-state discharge are quantitatively presented based on the developed global model. This provides a guide for future experiments plus further investigations using 2 and 3 D modeling.
IEC, HIPPER, global model, Helicon, space propulsion, thruster, plasma propulsion