Energy Supply for Heating the Slow Solar Wind Observed by Parker Solar Probe between 0.17 and 0.7 au

Abstract

Energy supply sources for the heating process in the slow solar wind remain unknown. The Parker Solar Probe (PSP) mission provides a good opportunity to study this issue. Recently, PSP observations have found that the slow solar wind experiences stronger heating inside 0.24 au. Here for the first time we measure in the slow solar wind the radial gradient of the low-frequency breaks on the magnetic trace power spectra and evaluate the associated energy supply rate. We find that the energy supply rate is consistent with the observed perpendicular heating rate calculated based on the gradient of the magnetic moment. Based on this finding, one could explain why the slow solar wind is strongly heated inside 0.25 au but expands nearly adiabatically outside 0.25 au. This finding supports the concept that the energy added from the energy-containing range is transferred by an energy cascade process to the dissipation range, and then dissipates to heat the slow solar wind. The related issues for further study are discussed.

arXiv comment6 pages, 4 figures, published by The Astrophysical Journal Letters

References in corpus (15)

• Solar Orbiter: Exploring the Sun-heliosphere connection
• A Model of Turbulence in Magnetized Plasmas: Implications for the Dissipation Range in the Solar Wind
• The Evolution and Role of Solar Wind Turbulence in the Inner Heliosphere
• Switchbacks in the near-Sun magnetic field: long memory and impact on the turbulence cascade
• Incorporating Kinetic Physics into a Two-Fluid Solar-Wind Model with Temperature Anisotropy and Low-Frequency Alfven-Wave Turbulence
• The Solar Probe Cup on Parker Solar Probe
• Proton Temperature Anisotropy Variations in Inner Heliosphere Estimated with First Parker Solar Probe Observations
• On slow solar wind with high Alfvénicity: from composition and microphysics to spectral properties
• Cross Helicity Reversals In Magnetic Switchbacks
• Enhanced Energy Transfer Rate in Solar Wind Turbulence Observed near the Sun from Parker Solar Probe
• On the 1/f spectrum in the solar wind and its connection with magnetic compressibility
• Radial evolution of the solar wind in pure high-speed streams: HELIOS revised observations
• Observational Test of Stochastic Heating in Low-$\beta$ Fast Solar Wind Streams
• The Enhancement of Proton Stochastic Heating in the near-Sun Solar Wind
• The low-frequency break observed in the slow solar wind magnetic spectra

Cited by in corpus (4)

• Parker Solar Probe: Four Years of Discoveries at Solar Cycle Minimum
• The evolution of compressible solar wind turbulence in the inner heliosphere: PSP, THEMIS and MAVEN observations
• Dominance of 2-Minute Oscillations near the Alfvén Surface
• Two Types of $1/f$ Range in Solar Wind Turbulence