Operation of Helicity Space's Peristaltic Magnetic Compressor-Expander Nozzle

Helicity Space is developing a fusion-based thruster concept which aims to magnetically compress pre-heated Taylor-State plasmas toward fusion conditions [1]. The thruster incorporates a magnetic nozzle that traps the target plasma and, like a Laval nozzle, has a compression and expansion section. The nozzle coils are connected as a transmission line with varying inductance and constant capacitance [2]. Sending two well-timed current pulses into the nozzle results in a traveling magnetic mirror that peristaltically compresses the trapped plasma to thermonuclear conditions. The expansion section reverses the process to cool the exhaust and generate thrust, with the possibility of mixing with cooler and denser plasma to adjust thrust and specific impulse.

The nozzle has been successfully tested to high-power (20 kV charge voltage and 3 kA peak instantaneous current) and fully integrated into the ECLAIR experiment for operation with the plasma [3]. We present the following results: (i) B-dot measurements of magnetic field propagation along the nozzle and matching analytical and numerical calculations; (ii) the status of attempts to visualize the evolution of the magnetic flux surfaces with a thermionic emitter [4]; (iii) results from 3D MHD simulations of four jets entering the nozzle to show how the timing of the jets with the nozzle fields affect plasma stability; (iv) measurements of ion temperature and plasma density using multi-chord interferometry and multi-chord ion doppler spectroscopy [5].

[1] S. You, AIAA Propulsion & Energy, AIAA-2020-3835 (2020)

[2] P. M. Bellan, Phys. Rev. Lett. 43, 858 (1979)

[3] Poster by S. Pree, et al.

[4] Poster by N. Marin, et al.

[5] Poster by S. Murray, et al.