Modification of Velocity Power Spectra by Thermal Plasma Instrumentation

[摘要] The upcoming Solar Probe Plus mission (Launch 2018) will launch with the newest and fastest space plasma instrumentation to date. The Solar Wind Electrons, Alphas, and Protons (SWEAP) instrument suite, which measures thermal plasma, will make measurements faster than the local gyro-frequency and proton plasma frequency. By developing an end-to-end computer model of a SWEAP instrument, this work explores the specific instrumental effects of thermal space plasma measurement, particularly in the reproduction of velocity power spectra, or Power Spectral Densities (PSDs). This model reproduces the slowest measurement cadence of the Solar Probe Cup (SPC), a Faraday cup (FC) style instrument on that will measure thermal plasma density, velocity, and temperature on SPP. By using the calibrated model to model measurement of fully determined and synthetic turbulent time series data, a consistent underestimation of the velocity power spectral indices has been quantified, with possible implications for previous missions flying similar instrumentation.

[发布机构] Department of Space Science, University of Alabama in Huntsville, Huntsville; AL; 35899, United States^1;Center for Space Plasma and Aeronomic Research (CSPAR), University of Alabama in Huntsville, Huntsville; AL; 35899, United States^2;Space Sciences Laboratory, University of California, 7 Gauss Way, Berkeley; CA; 94720, United States^3;NASA Marshall Space Flight Center (NASA/MSFC), 320 Sparkman Dr NW, Huntsville; AL; 35805, United States^4

[效力级别] 天文学 [学科分类] 天文学(综合)

[关键词] Calibrated model;Computer modeling;Model measurements;Plasma frequencies;Power spectral;Space plasmas;Thermal plasma;Turbulent time series