Langmuirprobe

The Langmuir probe is a diagnostic tool used in plasma physics to measure plasma parameters such as electron temperature, electron density, and plasma potential. It was developed by Irving Langmuir in the 1920s. The probe consists of a small electrode inserted into the plasma. By applying a voltage to the electrode and measuring the resulting current, one can determine the plasma properties.

There are two main types of Langmuir probes: single-probe and double-probe. The single-probe method involves sweeping the voltage applied to the electrode and measuring the current. The resulting current-voltage (I-V) characteristic curve provides information about the plasma parameters. The double-probe method uses two electrodes, one biased and one floating, to measure the plasma potential difference between them.

Langmuir probes are widely used in various plasma environments, including fusion reactors, semiconductor processing, and space plasma research. They are valued for their simplicity, low cost, and ability to provide real-time measurements. However, they have limitations, such as perturbation of the plasma by the probe itself and potential damage to the probe in high-energy plasma environments. Despite these limitations, Langmuir probes remain a fundamental tool in plasma diagnostics.