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Title: THE NONLINEAR AND NONLOCAL LINK BETWEEN MACROSCOPIC ALFVÉNIC AND MICROSCOPIC ELECTROSTATIC SCALES IN THE SOLAR WIND

The local heating of the solar-wind gas during its expansion represents one of the most intriguing problems in space plasma physics and is at present the subject of a relevant scientific effort. The possible mechanisms that could account for local heat production in the interplanetary medium are most likely related to the turbulent character of the solar-wind plasma. Nowadays, many observational and numerical analyses are devoted to the identification of fluctuation channels along which energy is carried from large to short wavelengths during the development of the turbulent cascade; these fluctuation channels establish the link between macroscopic and microscopic scales. In this Letter, by means of a quantitative comparison between in situ measurements in the solar wind from the STEREO spacecraft and numerical results from kinetic simulations, we identify an electrostatic channel of fluctuations that develops along the turbulent cascade in a direction parallel to the ambient magnetic field. This channel appears to be efficient in transferring the energy from large Alfvénic to short electrostatic acoustic-like scales up to a range of wavelengths where it can finally be turned into heat, even when the electron to proton temperature ratio is of the order of unity.
Authors:
; ; ; ;  [1] ; ;  [2]
  1. Dipartimento di Fisica and CNISM, Università della Calabria, I-87036 Rende (CS) (Italy)
  2. LESIA-Observatoire de Paris, CNRS, UPMC Université Paris 06, Université Paris-Diderot, 5 place J. Janssen, F-92190 Meudon (France)
Publication Date:
OSTI Identifier:
22365796
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astrophysical Journal Letters; Journal Volume: 788; Journal Issue: 1; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; COMPARATIVE EVALUATIONS; COMPUTERIZED SIMULATION; ELECTRONS; FLUCTUATIONS; HEAT PRODUCTION; HEATING; MAGNETIC FIELDS; NONLINEAR PROBLEMS; NUMERICAL ANALYSIS; PLASMA; PROTON TEMPERATURE; SOLAR WIND; SPACE