Figure 1

Experimental setup and the measured electron temperature, plasma density, and ion velocity in steady state. (a) Schematic diagram of the experimental setup. (b) The calculated magnetic field strength on axis, showing the divergent magnetic field. Measured x–z profiles of (c) the electron temperature \(T_e\), (d) the plasma density \(n_p\), and (e) the vector (arrows) and magnitude (colored scaling) of the ion velocity \({\mathbf{v}}_i\), together with the calculated magnetic field lines (solid lines). The conical structures of \(T_e\) and \(n_p\) are formed near the thruster exit and the \(n_p\) profile becomes nearly parabolic downstream, where the large amplitude wave is detected. The divergence of the ions are found to be smaller than that of the magnetic field lines, indicating the deviation of the ions from the magnetic field lines.