Solar Wind and PUI Proton Heating Rates and Turbulence Effects on Energetic Particles in the Heliosphere
Abstract We present a method for estimating the heating rate of solar wind (SW) and pickup ion (PUI) protons from their respective energy equations. Here, we estimate the heating rate for SW protons along the New Horizons (NH), Voyager 2 (V2), and Pioneer 10 (P10) trajectories using plasma measurements, rather than the magnetic field measurements. We also compute the heating rate for PUI protons for the first time along the NH direction. We find that the SW proton heating rate in the V2 direction is higher than that along the NH direction between ∼26 and ∼52 au. Along the P10 direction, the proton heating rate exceeds that of V2 between 20 and 38 au, but is less beyond 38 au. The heating rate differs along the spacecraft trajectories in the upwind and downwind directions. The PUI proton heating rate is found to be more than 2 orders of magnitude larger than that of SW protons between ∼26 and ∼52 au. The SW/PUI heating rate correlates with SW speed and SW/PUI temperature. We present a comparison between the injection rate of turbulence energy in the energy-containing range and the intensity profile of energetic particles in the ∼50–110 keV range as a function of distance along the NH and V2 directions. It suggests that turbulence may play an important role in the modulation of energetic particles throughout the heliosphere.
Authors
- JOHN D. RICHARDSON (ORCID: https://orcid.org/0000-0003-4041-7540)
- Jakobus Albertus Le Roux (ORCID: https://orcid.org/0000-0001-9199-2890)
- Justyna M. Sokół (ORCID: https://orcid.org/0000-0002-4173-3601)
- M. E. Hill (ORCID: https://orcid.org/0000-0002-5674-4936)
- M. Opher (ORCID: https://orcid.org/0000-0002-8767-8273)
- Bart Van Der Holst (ORCID: https://orcid.org/0000-0001-5260-3944)
- K. Dialynas (ORCID: https://orcid.org/0000-0002-5231-7929)
- Gary Paul Zank (ORCID: https://orcid.org/0000-0002-4642-6192)
- Sagar Ghimire
- Lingling Zhao (ORCID: https://orcid.org/0000-0002-4299-0490)
- V. Florinski (ORCID: https://orcid.org/0000-0001-5485-2872)
- Ashutosh Giri (ORCID: https://orcid.org/0000-0001-8501-0950)
- Parisa Mostafavi (ORCID: https://orcid.org/0000-0002-3808-3580)
- H. A. Elliott (ORCID: https://orcid.org/0000-0003-2297-3922)
- Romina Nikoukar (ORCID: https://orcid.org/0000-0002-8608-2822)
- Bishwas L. Shrestha (ORCID: https://orcid.org/0000-0002-5247-4107)
- Bingbing Wang (ORCID: https://orcid.org/0000-0002-6000-1262)
- L. Adhikari (ORCID: https://orcid.org/0000-0003-1549-5256)
- David J. McComas (ORCID: https://orcid.org/0000-0001-6160-1158)
Institutions
- Boston University (US)
- Southwest Research Institute (US)
- Princeton University (US)
- Johns Hopkins University Applied Physics Laboratory (US)
- Massachusetts Institute of Technology (US)
- University of Alabama in Huntsville (US)
Publication Details
- Journal
- The Astrophysical Journal
- Published
- 2026-11-06
- DOI
- https://doi.org/10.3847/1538-4357/aeacc4
- Primary Topic
- Solar and Space Plasma Dynamics
- Type
- article
- Field-Weighted Citation Impact
- 0.00