Intermittent turbulence as the driver of stochastic heating in the near-Sun solar wind
Abstract
Understanding the mechanism by which the energy is dissipated at small scales to heat the outer corona and expanding solar wind, is a primary goal of the Parker Solar Probe (PSP) mission, and an outstanding question in heliophysics. Recent observational case studies have suggested that the dominant dissipation mechanism(s), stochastic heating (SH) or resonant heating (RH), may be modulated by the Alfvén `surface' (MA = 1), while theoretical and simulation works predict that the mechanism should be modulated by the level of turbulence imbalance. We measure the local energy transfer (LET) rate from $9.8$ to $55$ solar radii from PSP observations, showing that the LET rate peaks at MA ∼ 0.4 − 0.9. We connect enhanced LET rates to signatures of intermittency, highlighting the key role that intermittent fluctuations play in heating the near-Sun solar wind. We compare the LET rate with estimates of the SH rate, finding that below ∼ 15 solar radii the SH heating rate matches the LET rate provided intermittency is accounted for, regardless of MA, while farther from the Sun, SH is unable to account for the observed LET rate. In contrast to predictions by recent theoretical works, this implies that `imbalanced' intermittent stochastic heating may be a viable mechanism to heat highly imbalanced, low-β collisionless plasmas, and is likely an important mechanism of dissipation in the outer solar corona and near-Sun solar wind.
Related
- Solar Wind and PUI Proton Heating Rates and Turbulence Effects on Energetic Particles in the Heliosphere
- Collisionless and collisional kinetics of a plasma atmosphere with spatially and temporally intermittent heating at its base
- Ion Heating in Pair-loaded Relativistic Turbulence
- Solar-wind proton heating and its effect on the temperature anisotropy evolution between 0.05 and 1 au
- Internal heating in rapidly rotating convection is not a shortcut to geostrophic turbulence
BibTeX
@misc{ervin2026intermittent,
title = {{Intermittent turbulence as the driver of stochastic heating in the near-Sun solar wind}},
author = {Tamar Ervin and Trevor A. Bowen and Alfred Mallet and Stuart D. Bale and Kristopher G. Klein and Mihailo Martinovic and Benjamin D. G. Chandran and Philip A. Isenberg and Orlando Romeo and Roberto Livi and Ali Rahmati and Davin Larson},
howpublished = {arXiv},
year = {2026},
month = oct,
doi = {10.48550/arxiv.2610.24296},
eprint = {2610.24296},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2610.24296},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - Intermittent turbulence as the driver of stochastic heating in the near-Sun solar wind
AU - Tamar Ervin
AU - Trevor A. Bowen
AU - Alfred Mallet
AU - Stuart D. Bale
AU - Kristopher G. Klein
AU - Mihailo Martinovic
AU - Benjamin D. G. Chandran
AU - Philip A. Isenberg
AU - Orlando Romeo
AU - Roberto Livi
AU - Ali Rahmati
AU - Davin Larson
PY - 2026
DA - 2026/10/16
PB - arXiv
DO - 10.48550/arxiv.2610.24296
UR - https://arxiv.org/abs/2610.24296
AB - Understanding the mechanism by which the energy is dissipated at small scales to heat the outer corona and expanding solar wind, is a primary goal of the Parker Solar Probe (PSP) mission, and an outstanding question in heliophysics. Recent observational case studies have suggested that the dominant dissipation mechanism(s), stochastic heating (SH) or resonant heating (RH), may be modulated by the Alfvén `surface' (M_A = 1), while theoretical and simulation works predict that the mechanism should be modulated by the level of turbulence imbalance. We measure the local energy transfer (LET) rate from $9.8$ to $55$ solar radii from PSP observations, showing that the LET rate peaks at M_A ∼ 0.4 − 0.9. We connect enhanced LET rates to signatures of intermittency, highlighting the key role that intermittent fluctuations play in heating the near-Sun solar wind. We compare the LET rate with estimates of the SH rate, finding that below ∼ 15 solar radii the SH heating rate matches the LET rate provided intermittency is accounted for, regardless of M_A, while farther from the Sun, SH is unable to account for the observed LET rate. In contrast to predictions by recent theoretical works, this implies that `imbalanced' intermittent stochastic heating may be a viable mechanism to heat highly imbalanced, low-β collisionless plasmas, and is likely an important mechanism of dissipation in the outer solar corona and near-Sun solar wind.
ER -