The Langmuir Probe and Waves (LPW) instrument is part of the Particles and Fields (P & F) Package and determines ionospheric properties, wave heating of the upper atmosphere, and solar EUV input to the atmosphere.
Goals:
- Measure the in situ electron density and electron temperature from the ionospheric peak up to the nominal ionopause location; measure the electric field wave power important for ion heating
- Characterize the basic state of the ionosphere—its global structure, variability, and thermal properties
- Determine the effects of solar wind generated plasma waves and auroral precipitation on ionosphere heating and relationship to plasma escape
- Determine the electron temperatures required for deriving ion recombination rates and ionospheric chemistry
- Identify the ionopause and detached, escaping ionosphere clouds
Observations:
- Electron temperature and number density throughout upper atmosphere
- Electric field wave power at low frequencies important for ion heating
- Wave spectra of naturally emitted and actively stimulated Langmuir waves to calibrate density measurements
Technical details and heritage:
- Cylindrical sensors on two 7-meter booms
- Sensor I-V sweeps (at least ±50 V range)
- Low frequency (f: 0.05-10 Hz) E-field power; sensitivity 10-8 (V/m)2/Hz (f0/f)2 where fo=10 Hz and 100% bandwidth
- E-Spectra measurements up to 2 MHz
- White noise (50 kHz – 2 MHz ) sounding
- Thermal Electron density 100 to 106 cm-3
- Electron temperatures 500 to 5000oK
- Heritage from THEMIS and RBSP
Instrument publications:
- Ionospheric plasma density variations observed at Mars by MAVEN/LPW
(Geophysical Research Letters article—published online November 2015)—Download PDF (1 MB) - The Langmuir Probe and Waves (LPW) Instrument for MAVEN
(Space Science Reviews article—published online September 2015)—Download PDF (4 MB)
Bob Ergun (LASP) is the instrument lead for the LPW.
MAVEN Science Community Workshop Presentations
(Dec. 2, 2012)