A combination Langmuir/Mach probe is radially scanned approximately 2.5" above the bottom endcap set of magnet & electrode rings.
Electron temperature and plasma density is measured using a single tip, radially scannable Langmuir probe. Collected current and sweeping voltage is measured using NI PXI-4462 4 ch. AI (24 Bit, 200 kS/s).
A Mach probe is used to measure the difference in upstream and downstream ion saturation current to infer flow.
Other planned diagnostics include:
- 1 mm Mach-Zehndner interferometer for line integrated density measurements
- Ion Doppler Spectroscopy can non-intrusively measure ion velocity through the Doppler shift of spectral emission
- Laser Induced Fluorescence for non-intrusive, high-resolution measurements of particle (ions, neutrals) velocity distribution
- Emissive probe to measure plasma potential, which can be related to flow
- B-dot coil array for magnetic fluctuations