Hiroaki Fujitsuka

High-Density Helicon Plasma Sources: Basics and Application to Electrodeless Electric Propulsion

The development of unique, high-density helicon plasma sources is described. Characterization of the largest and the smallest source sizes is made along with a discussion of particle production efficiency using Ar gas. Next, we describe an application of helicon sources to plasma propulsion using a new advanced concept without any eroding electrodes, as a review of our Helicon Electrodeless Advanced Thruster (HEAT) project.

Study on electrodeless electric propulsion in high-density helicon plasma with permanent magnets

To establish electrodeless electric propulsion, we have been developing a new electrodeless plasma acceleration thruster using high-density helicon plasmas and permanent magnets, and characterizing them by, e.g., electrostatic and magnetic probes, a high-resolution spectrometer (measuring argon line intensity and line intensity ratio to derive plasma parameters), and a high-speed camera measurements (deriving radial distribution of electron density), in addition to a laser induced fluorescence (LIF) method to measure plasma flow velocity, where they are under development. Here, we will present preliminary acceleration methods using such as Rotating Magnetic Field coil and m = 0 coil along with results of various measurements mentioned above to estimate the plasma performance.

Characteristics of rf-produced, high-density plasma with very small diameter

To investigate characteristics of helicon plasma with a very small diameter, we have developed the Small Helicon Device (SHD) and measured the electron density under various conditions over a wide range of radio frequencies. Using a tube with inner diameter of 20 mm, an electron density ne of ~ 10 13 cm near the antenna region was obtained with an excitation frequency f of 7 MHz, rf power Prf of ~ 1000 W, and axial magnetic field in the magnet coil region B of 560 G. In the case of an inner diameter of 5 (10) mm under conditions of f = 12 (7) MHz, Prf ~ 1000 W, and B = 280 G, ne of ~ 10 11 cm was succesfully achieved even away from the antenna region.