Lectures

NEVF173 – Diagnostics in space plasmas (2/1, C+Ex)

Lubomír Přech, Ondřej Santolík


Diagnostics of low temperature plasma in space, measuring of fluxes and distribution functions of electrons, ions, and neutral particles, particle detectors. Measurements of electric and magnetic fields. Overview of ground measurements including monitors of lightning activity. Active experiments in space. Calculation of plasma parameters from measurable quantities. Problems of intercalibration.

  • Classification of measurement methods: In-situ and remote measurements, ground and satellite measurements, sounding rockets, aircraft and baloon measurements.
  • Introduction to instrument electronics: Amplifier, frequency and phase characteristics. Adjustment of frequency spectrum (filtering). Sampling theorem, Nyquist frequency, antialiasing and reconstruction filter. Analog-to-digital and digital-to-analog conversion.
  • Diagnostics of low-temparature plasma: Langmuir sondes, retarding potential analyzers.
  • Measurements of energy and velocity distribution function of charged particles: Particle detectors (current measurements, channeltrons and microchannel plates, seminconductor detectors). Electrostatic analyzers, techniques of measurement 2D and 3D distribution velocity distribution function. Meaurement of pitch-angle distribution. Calibration of particle detectors. Effects of spacecraft potential and space radiation on measurements.
  • Ion analyzers with mass resolution: Separation using magnetic field, radiofrequency and time-of-flight techniques.
  • Measurements of neutral particles: Analyzers of neutral particles, imaging using neutral particles.
  • Measurements of energetic particle spectra, dosimetry: Registration of high-energy particles and rtg/gamma radation. Scintilators and solid-state detectors.
  • Measurements of electric and magnetic fields: Measurements of DC and AC fields across a wide range of frequencies. Spacecraft potential. Effects of photocurrent. Scalar and vector measurements of magnetic field, measurements of DC and AC magnetic field (flux-gate and search-coil magnetometers). Measurements of electric and magnetic fields using electron drift. Determining plasma wave parameters, analysis onboard a spacecraft. Wave-particle interactions, particle correlators.
  • Dust detection in space: Dust in solar system, history of detection of dust particles, dedicated dust detectors, alternative means of dust detection (Faraday cups, electric antennas).
  • Active experiments: Active experiments in space plasma and methods used for their realization. Plasma interaction with particle beams, changes of object potential.
  • Ground-based measurements: Measurements of electromagnetic signals related to storm activity, methodsof detection of lightning discharges and above-cloud phenomena, optical measurement techniques (cameras and photometers). Measurements of electric and geomagnetic fields, geomagnetic indices. Ionospheric sounding (digisonde, incoherent scattering). Global navigation satellite system in ionospheric measurements (TEC).
  • Calculation of plasma parameters from measurable quantities: Determining the orientation and parameters of disconttinuities. Multipoint measurements. Intercalibration between instruments and satellites.