A magnetic reconnecting helicon thruster

Plasma propulsion has been used in station keeping but has not yet been employed in deep space missions due to low efficiency and short lifetimes. Helicons are interesting for this application due to higher plasma densities per watt input power; however, they suffer from poor electrical efficiency due to low ion temperatures and poor detachment from field lines at the exhaust. Previous works used auxiliary ion heating at the cost of higher power requirements. Alternatively, novel magnetic configurations can be used to instigate reconnection. We have designed a helicon thruster utilizing induced magnetic reconnection to increase ion temperatures. As ions exit the current sheet they are accelerated to the Alfven speed by the reconnected field, resulting in higher ion momentum. Optimization of the magnetic geometry to improve detachment can also result in increased thrust. The thruster has three primary systems: RF input power, confining magnetic coils, and a shear coil. The shear coil near the exhaust has opposite magnetic polarity to the confining coils, generating a magnetic null, and instigating reconnection. Initial simulations have modeled the antenna-plasma coupling and the reconnecting magnetic topology. This work was supported by Nuclear Regulatory Commission grant 31310021M0034.