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Title: Decay of Solar Wind Turbulence behind Interplanetary Shocks

Abstract

We investigate the decay of magnetic and kinetic energies behind IP shocks with motivation to find a relaxation time when downstream turbulence reaches a usual solar wind value. We start with a case study that introduces computation techniques and quantifies a contribution of kinetic fluctuations to the general energy balance. This part of the study is based on high-time (31 ms) resolution plasma data provided by the Spektr-R spacecraft. On the other hand, a statistical part is based on 92 s Wind plasma and magnetic data and its results confirm theoretically established decay laws for kinetic and magnetic energies. We observe the power-law behavior of the energy decay profiles and we estimated the power-law exponents of both kinetic and magnetic energy decay rates as −1.2. We found that the decay of MHD turbulence does not start immediately after the IP shock ramp and we suggest that the proper decay of turbulence begins when a contribution of the kinetic processes becomes negligible. We support this suggestion with a detailed analysis of the decay of turbulence at the kinetic scale.

Authors:
; ;  [1];  [2]
  1. Charles University, Faculty of Mathematics and Physics, V Holesovickach 2, Prague, CZ-18000 (Czech Republic)
  2. Dipartimento di Fisica e Astronomia, Universita degli Studi di Firenze, I-50125 Firenze (Italy)
Publication Date:
OSTI Identifier:
22663360
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astrophysical Journal; Journal Volume: 844; 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; DECAY; ENERGY BALANCE; FLUCTUATIONS; INTERPLANETARY MAGNETIC FIELDS; INTERPLANETARY SPACE; MAGNETOHYDRODYNAMICS; PLASMA; RELAXATION TIME; RESOLUTION; SHOCK WAVES; SOLAR WIND; SPACE VEHICLES; TURBULENCE

Citation Formats

Pitňa, Alexander, Šafránková, Jana, Němeček, Zdeněk, and Franci, Luca, E-mail: offelius@gmail.com. Decay of Solar Wind Turbulence behind Interplanetary Shocks. United States: N. p., 2017. Web. doi:10.3847/1538-4357/AA7BEF.
Pitňa, Alexander, Šafránková, Jana, Němeček, Zdeněk, & Franci, Luca, E-mail: offelius@gmail.com. Decay of Solar Wind Turbulence behind Interplanetary Shocks. United States. doi:10.3847/1538-4357/AA7BEF.
Pitňa, Alexander, Šafránková, Jana, Němeček, Zdeněk, and Franci, Luca, E-mail: offelius@gmail.com. Thu . "Decay of Solar Wind Turbulence behind Interplanetary Shocks". United States. doi:10.3847/1538-4357/AA7BEF.
@article{osti_22663360,
title = {Decay of Solar Wind Turbulence behind Interplanetary Shocks},
author = {Pitňa, Alexander and Šafránková, Jana and Němeček, Zdeněk and Franci, Luca, E-mail: offelius@gmail.com},
abstractNote = {We investigate the decay of magnetic and kinetic energies behind IP shocks with motivation to find a relaxation time when downstream turbulence reaches a usual solar wind value. We start with a case study that introduces computation techniques and quantifies a contribution of kinetic fluctuations to the general energy balance. This part of the study is based on high-time (31 ms) resolution plasma data provided by the Spektr-R spacecraft. On the other hand, a statistical part is based on 92 s Wind plasma and magnetic data and its results confirm theoretically established decay laws for kinetic and magnetic energies. We observe the power-law behavior of the energy decay profiles and we estimated the power-law exponents of both kinetic and magnetic energy decay rates as −1.2. We found that the decay of MHD turbulence does not start immediately after the IP shock ramp and we suggest that the proper decay of turbulence begins when a contribution of the kinetic processes becomes negligible. We support this suggestion with a detailed analysis of the decay of turbulence at the kinetic scale.},
doi = {10.3847/1538-4357/AA7BEF},
journal = {Astrophysical Journal},
number = 1,
volume = 844,
place = {United States},
year = {Thu Jul 20 00:00:00 EDT 2017},
month = {Thu Jul 20 00:00:00 EDT 2017}
}