First Application of a Digital Mirror Langmuir Probe for Real-Time Plasma Diagnosis

First Application of a Digital Mirror Langmuir Probe for Real-Time Plasma Diagnosis

First Application of a Digital Mirror Langmuir Probe for Real-Time Plasma Diagnosis 150 150 UKAEA Opendata
UKAEA-CCFE-PR(21)32

First Application of a Digital Mirror Langmuir Probe for Real-Time Plasma Diagnosis

For the first time, a digital Mirror Langmuir probe (MLP) has successfully sampled plasma temperature, ion saturation current, and floating potential together on a single probe tip in real time in a radio-frequency driven helicon linear plasma device. This is accomplished by feedback control of the bias sweep to ensure a good fit to I-V characteristics with a high frequency, high power digital amplifier and field-programmable gate array (FPGA) controller. Measurements taken by the MLP were validated by a low speed I-V characteristic manually collected during static plasma conditions. Plasma fluctuations, induced by varying the axial magnetic field (f̃= 10 Hz), were also successfully monitored with the MLP. Further refinement of the digital MLP pushes it towards a turn-key system that minimizes the time to deployment and lessens the learning curve, positioning the digital MLP as a capable diagnostic for the study of low radio-frequency plasma physics. These demonstrations bolster confidence in fielding such digital MLP diagnostics in magnetic confinement experiments with high spatial and adequate temporal resolution such as edge plasma, scrape-off layer, and divertor probes.

Collection:
Journals
Journal:
Review of Scientific Instruments
Publisher:
AIP (American Institute of Physics)