Interferometry is a diagnostic technique that utilizes the interference of electromagnetic waves to determine the electron density in a plasma. By measuring the phase shift or intensity changes in the transmitted or reflected waves, the electron density can be inferred.

Langmuir probe diagnostics measure the plasma potential and electron density by inserting a metallic probe into the plasma and analyzing the current-voltage characteristics. The probe's floating potential corresponds to the plasma potential.

Spectroscopy is a diagnostic technique that analyzes the emission or absorption of light by plasma particles. By studying the spectral lines, one can determine various plasma parameters such as temperature, density, and composition.

Magnetic probe diagnostics measure the magnetic field within a plasma. By inserting a small magnetic sensor into the plasma, the local magnetic field can be determined, providing information about the plasma's magnetic field structure and topology.

Scattering diagnostics involve directing electromagnetic waves (e.g., microwaves, lasers) into the plasma and analyzing the scattered waves. The scattering process provides information about plasma parameters such as density, temperature, and fluctuations.

A bolometer is a diagnostic tool used to measure the total radiated power emitted by a plasma. It is typically composed of a temperature-sensitive material that converts the incident radiation into a measurable electrical signal.

Doppler spectroscopy is a diagnostic technique that utilizes the Doppler shift in spectral lines to determine the ion temperature in a plasma. By measuring the shift in the wavelength or frequency of emitted or absorbed light, the ion velocity distribution and temperature can be inferred.

Thomson scattering diagnostics involve directing a laser beam into the plasma and analyzing the scattered light. The scattering process provides information about the electron temperature and density. The scattered light's spectral broadening is related to the electron thermal motion.

Stark spectroscopy is a diagnostic technique that utilizes the Stark effect to measure the electric field in a plasma. The Stark effect refers to the splitting of spectral lines in the presence of an electric field. By analyzing the splitting of spectral lines, the electric field strength can be determined.

A particle energy analyzer is a diagnostic tool used to measure the energy distribution of charged particles (ions or electrons) in a plasma. It typically consists of a series of electrostatic or magnetic fields that separate particles based on their energy.

A Rogowski coil is a diagnostic tool used to measure the plasma current. It consists of a coil wrapped around the plasma vessel or a conductor carrying the plasma current. The changing magnetic field produced by the plasma current induces a voltage in the coil, which is proportional to the current.

Microwave interferometry is a diagnostic technique that utilizes the interference of microwave waves to determine the electron density in a plasma. By measuring the phase shift or intensity changes in the transmitted or reflected waves, the electron density can be inferred.

Doppler spectroscopy can also be used to measure the plasma rotation velocity. By analyzing the Doppler shift in spectral lines due to the plasma's rotation, the velocity of the plasma can be determined.

A Fabry-Perot interferometer is a diagnostic tool used to measure the spectral line profiles of plasma emissions. It consists of two highly reflective mirrors placed parallel to each other, forming a resonant cavity. The interference of light within the cavity produces a series of bright and dark fringes, which can be used to analyze the spectral line shape and extract information about plasma parameters.

Spectroscopy can also be used to measure the impurity concentration in a plasma. By analyzing the spectral lines emitted by impurity ions, the type and amount of impurities present in the plasma can be determined.