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Energy Transfer, Discontinuities, and Heating in the Inner Heliosphere Measured with a Weak and Local Formulation of the Politano-Pouquet Law
| Author | David, V.; Galtier, S.; Sahraoui, F.; Hadid, L.~Z.; |
| Keywords | Parker Data Used; interplanetary turbulence; Space plasmas; Solar wind; 830; 1544; 1534; Astrophysics - Solar and Stellar Astrophysics; Physics - Plasma Physics; Physics - Space Physics |
| Abstract | The solar wind is a highly turbulent plasma for which the mean rate of energy transfer ɛ has been measured for a long time using the Politano-Pouquet (PP98) exact law. However, this law assumes statistical homogeneity that can be violated by the presence of discontinuities. Here, we introduce a new method based on the inertial dissipation $ D _I^{\sigma }$ whose analytical form is derived from incompressible magnetohydrodynamics; it can be considered as a weak and local (in space) formulation of the PP98 law whose expression is recovered after integration in space. We used $ D _I^{\sigma }$ to estimate the local energy transfer rate at scale {\ensuremath{\sigma}} from the THEMIS-B and Parker Solar Probe data taken in the solar wind at different heliospheric distances. Our study reveals that discontinuities near the Sun lead to a strong energy transfer that affects a wide range of scales {\ensuremath{\sigma}}. We also observe that switchbacks seem to be characterized by a singular behavior with an energy transfer varying as {\ensuremath{\sigma}} $^{-3/4}$, which slightly differs from classical discontinuities characterized by a {\ensuremath{\sigma}} $^{-1}$ scaling. A comparison between the measurements of ɛ and $ D _I^{\sigma }$ shows that in general the latter is significantly larger than the former. |
| Year of Publication | 2022 |
| Journal | \apj |
| Volume | 927 |
| Number of Pages | 200 |
| Section | |
| Date Published | mar |
| ISBN | |
| URL | |
| DOI | 10.3847/1538-4357/ac524b |
