Published March 8, 2024 | Version v1
Journal article Open

Solar Wind Density and Core Temperature Derived from the PSP Quasi-thermal Noise Measurements

  • 1. Department of Earth and Space Sciences, Southern University of Science and Technology, Shenzhen, People's Republic of China;
  • 2. Department of Earth and Space Sciences, Southern University of Science and Technology, Shenzhen, People's Republic of China
  • 3. Lunar and Planetary Laboratory, University of Arizona, Tucson, AZ, USA;
  • 4. LESIA, Observatoire de Paris, Meudon, France
  • 5. Royal Belgian Institute for Space Aeronomy (BIRA-IASB), Space Physics, Solar-Terrestrial Center of Excellence, Brussels, Belgium
  • 6. Center for Space Radiation (CSR), Georges Lemaître Centre for Earth and Climate Research (TECLIM), Earth and Life Institute—Climate Sciences (ELI-C)
  • 7. Space Sciences Laboratory, University of California, Berkeley, CA 94720-7450, USA

Description

Quasi-thermal noise (QTN) spectroscopy is a valuable method to deduce important parameters in space plasma, such as plasma density and temperature, especially when direct particle measurements are not available. The present study develops a new fitting method to fit the QTN spectra observed by the Parker Solar Probe (PSP) with a comprehensive theoretical QTN spectral model. By combining the steepest descent and Levenberg–Marquardt algorithms, the new method is more flexible with initial guess values but still yields reliable solar wind electron density and temperature values. The new method is applied to derive the solar wind density and core temperature from the QTN measurements during 10 encounters of PSP. The electron density and temperature values obtained vary with the radial distance from the Sun as ner−2.12 and Ter−0.71, both of which are consistent with existing models and previous results.

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