Including sheath effects in the interpretation of planar retarding potential analyzer’s low-energy ion data
| Autor: | L. E. Fisher, Kristina A. Lynch, P. A. Fernandes, Joran Moen, Marc Lessard, S. P. Powell, M. Zettergren, T. A. Bekkeng, P. Horak, R. J. Miceli |
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| Rok vydání: | 2016 |
| Předmět: |
Physics
Debye sheath Spectrum analyzer Sounding rocket 010504 meteorology & atmospheric sciences business.industry Detector Plasma 01 natural sciences Ionospheric sounding 010305 fluids & plasmas symbols.namesake Optics 0103 physical sciences symbols Langmuir probe business Electrostatic analyzer Instrumentation 0105 earth and related environmental sciences |
| Zdroj: | Review of Scientific Instruments. 87:043504 |
| ISSN: | 1089-7623 0034-6748 |
| DOI: | 10.1063/1.4944416 |
| Popis: | The interpretation of planar retarding potential analyzers (RPA) during ionospheric sounding rocket missions requires modeling the thick 3D plasma sheath. This paper overviews the theory of RPAs with an emphasis placed on the impact of the sheath on current-voltage (I-V) curves. It then describes the Petite Ion Probe (PIP) which has been designed to function in this difficult regime. The data analysis procedure for this instrument is discussed in detail. Data analysis begins by modeling the sheath with the Spacecraft Plasma Interaction System (SPIS), a particle-in-cell code. Test particles are traced through the sheath and detector to determine the detector's response. A training set is constructed from these simulated curves for a support vector regression analysis which relates the properties of the I-V curve to the properties of the plasma. The first in situ use of the PIPs occurred during the MICA sounding rocket mission which launched from Poker Flat, Alaska in February of 2012. These data are presented as a case study, providing valuable cross-instrument comparisons. A heritage top-hat thermal ion electrostatic analyzer, called the HT, and a multi-needle Langmuir probe have been used to validate both the PIPs and the data analysis method. Compared to the HT, the PIP ion temperature measurements agree with a root-mean-square error of 0.023 eV. These two instruments agree on the parallel-to-B plasma flow velocity with a root-mean-square error of 130 m/s. The PIP with its field of view aligned perpendicular-to-B provided a density measurement with an 11% error compared to the multi-needle Langmuir Probe. Higher error in the other PIP's density measurement is likely due to simplifications in the SPIS model geometry. |
| Databáze: | OpenAIRE |
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