On the Fourier Contribution of Strong Current Sheets to the High‐Frequency Magnetic Power SpectralDensity of the Solar Wind

Solar wind current sheets have been extensively studied at 1 AU. The recent advent of Parker Solar Probe and Solar Orbiter (SolO) has enabled us to study these structures at a range of heliocentric distances.We present SolO observations of current sheets in the solar wind at heliocentric distances between 0.55 and 0.85 AU, some of which show signatures of ongoing magnetic reconnection. We develop a method to find the deHoffman-Teller frame which minimizes the Y-component (the component tangential to the spacecraft orbit) of the electric field. Using the electric field measurements from RPW and magnetic field measurements from MAG, we use our method to determine the deHoffman-Teller frame of solar wind current sheets. The same method can also be used on the Alfv&#233;nic turbulence and structures found in the solar wind to obtain a measure of the solar wind velocity.Our preliminary results show a good agreement between our modified deHoffmann-Teller analysis based on the single component E-field, and the conventional deHoffman-Teller analysis based on 3D plasma velocity measurements from PAS. This opens up the possibility to use the RPW and MAG data to obtain an estimate of the solar wind velocity when particle data is unavailable.

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Evolution of the MHD turbulence properties in the inner heliosphere with the PSP/SolO alignment data

10.5194/egusphere-egu21-14585 ◽

2021 ◽

Author(s):

Daniele Telloni ◽

Keyword(s):

Solar Wind ◽

High Frequency ◽

Interplanetary Space ◽

Solar Wind Plasma ◽

Radial Dependence ◽

Physical Processes ◽

Temperature Anisotropy ◽

Mhd Turbulence ◽

Radial Evolution ◽

Inner Heliosphere

Radial alignments between pairs of spacecraft is the only way to observationally investigate the turbulent evolution of the solar wind as it expands throughout interplanetary space. On September 2020 Parker Solar Probe (PSP) and Solar Orbiter (SolO) were nearly perfectly radially aligned, with PSP orbiting around its perihelion at 0.1 au (and crossing the nominal Alfv&#233;n point) and SolO at 1 au. PSP/SolO joint observations of the same solar wind plasma allow the extraordinary and unprecedented opportunity to study how the turbulence properties of the solar wind evolve in the inner heliosphere over the wide distance of 0.9 au. The radial evolution of (i) the MHD properties (such as radial dependence of low- and high-frequency breaks, compressibility, Alfv&#233;nic content of the fluctuations), (ii) the polarization status, (iii) the presence of wave modes at kinetic scale as well as their distribution in the plasma instability-temperature anisotropy plane are just few instances of what can be addressed. Of furthest interest is the study of whether and how the cascade transfer and dissipation rates evolve with the solar distance, since this has great impact on the fundamental plasma physical processes related to the heating of the solar wind. In this talk I will present some of the results obtained by exploiting the PSP/SolO alignment data.

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Ultrahigh-resolution model of a breakout CME embedded in the solar wind

Astronomy and Astrophysics ◽

10.1051/0004-6361/201832976 ◽

2018 ◽

Vol 620 ◽

pp. A57 ◽

Cited By ~ 5

Author(s):

S. Hosteaux ◽

E. Chané ◽

B. Decraemer ◽

D.-C. Talpeanu ◽

S. Poedts

Keyword(s):

Solar Wind ◽

Adaptive Mesh Refinement ◽

Flux Rope ◽

Adaptive Mesh ◽

Electrical Current ◽

Substantial Effect ◽

Small Scale ◽

Release Process ◽

Ultrahigh Resolution ◽

Current Sheets

Aims. We investigate the effect of a background solar wind on breakout coronal mass ejections, in particular, the effect on the different current sheets and the flux rope formation process. Methods. We obtained numerical simulation results by solving the magnetohydrodynamics equations on a 2.5D (axisymmetric) stretched grid. Ultrahigh spatial resolution is obtained by applying a solution adaptive mesh refinement scheme by increasing the grid resolution in regions of high electrical current, that is, by focussing on the maximum resolution of the current sheets that are forming. All simulations were performed using the same initial base grid and numerical schemes; we only varied the refinement level. Results. A background wind that causes a surrounding helmet streamer has been proven to have a substantial effect on the current sheets that are forming and thus on the dynamics and topology of the breakout release process. Two distinct ejections occur: first, the top of the helmet streamer detaches, and then the central arcade is pinched off behind the top of the helmet streamer. This is different from the breakout scenario that does not take the solar wind into account, where only the central arcade is involved in the eruption. In the new ultrahigh-resolution simulations, small-scale structures are formed in the lateral current sheets, which later merge with the helmet streamer or reconnect with the solar surface. We find that magnetic reconnections that occur at the lateral breakout current sheets deliver the major kinetic energy contribution to the eruption and not the reconnection at the so-called flare current sheet, as was seen in the case without background solar wind.

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Extreme value theory in the solar wind: the role of current sheets

Monthly Notices of the Royal Astronomical Society ◽

10.1093/mnras/stz2668 ◽

2019 ◽

Vol 490 (2) ◽

pp. 1879-1893

Author(s):

Tiago F P Gomes ◽

Erico L Rempel ◽

Fernando M Ramos ◽

Suzana S A Silva ◽

Pablo R Muñoz

Keyword(s):

Solar Wind ◽

Power Spectra ◽

Value Theory ◽

Extreme Value ◽

Extreme Value Statistics ◽

Intermittent Turbulence ◽

Current Sheets ◽

Developed Turbulence ◽

The Right

ABSTRACT This article provides observational evidence for the direct relation between current sheets, multifractality and fully developed turbulence in the solar wind. In order to study the role of current sheets in extreme-value statistics in the solar wind, the use of magnetic volatility is proposed. The statistical fits of extreme events are based on the peaks-over-threshold (POT) modelling of Cluster 1 magnetic field data. The results reveal that current sheets are the main factor responsible for the behaviour of the tail of the magnetic volatility distributions. In the presence of current sheets, the distributions display a positive shape parameter, which means that the distribution is unbounded in the right tail. Thus the appearance of larger current sheets is to be expected and magnetic reconnection events are more likely to occur. The volatility analysis confirms that current sheets are responsible for the −5/3 Kolmogorov power spectra and the increase in multifractality and non-Gaussianity in solar wind statistics. In the absence of current sheets, the power spectra display a −3/2 Iroshnikov–Kraichnan law. The implications of these findings for the understanding of intermittent turbulence in the solar wind are discussed.

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High-latitude Conic Current Sheets in the Solar Wind

The Astrophysical Journal ◽

10.3847/1538-4357/836/1/108 ◽

2017 ◽

Vol 836 (1) ◽

pp. 108 ◽

Cited By ~ 9

Author(s):

Olga V. Khabarova ◽

Helmi V. Malova ◽

Roman A. Kislov ◽

Lev M. Zelenyi ◽

Vladimir N. Obridko ◽

...

Keyword(s):

Solar Wind ◽

High Latitude ◽

Current Sheets

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Structure of Current Sheets with Quasi-Adiabatic Dynamics of Particles in the Solar Wind

Cosmic Research ◽

10.1134/s0010952518060060 ◽

2018 ◽

Vol 56 (6) ◽

pp. 462-470 ◽

Cited By ~ 2

Author(s):

Kh. V. Malova ◽

V. Yu. Popov ◽

O. V. Khabarova ◽

E. E. Grigorenko ◽

A. A. Petrukovich ◽

...

Keyword(s):

Solar Wind ◽

Current Sheets ◽

Adiabatic Dynamics ◽

Dynamics Of Particles

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Magnetohydrodynamic Modeling of the Solar Wind Key Parameters and Current Sheets in the Heliosphere: Radial and Solar Cycle Evolution

The Astrophysical Journal ◽

10.3847/1538-4357/ab712c ◽

2020 ◽

Vol 892 (1) ◽

pp. 12 ◽

Cited By ~ 1

Author(s):

E. V. Maiewski ◽

R. A. Kislov ◽

O. V. Khabarova ◽

H. V. Malova ◽

V. Yu. Popov ◽

...

Keyword(s):

Solar Wind ◽

Solar Cycle ◽

Current Sheets

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Current sheets from Ulysses observation

Annales Geophysicae ◽

10.5194/angeo-29-237-2011 ◽

2011 ◽

Vol 29 (2) ◽

pp. 237-249 ◽

Cited By ~ 33

Author(s):

B. Miao ◽

B. Peng ◽

G. Li

Keyword(s):

Solar Wind ◽

Current Sheet ◽

Solar Wind Plasma ◽

Mhd Turbulence ◽

Automatic Data ◽

Flux Tubes ◽

Current Sheets ◽

Solar Origin ◽

Turbulence Intermittency ◽

Solar Wind Magnetic Field

Abstract. Current sheet is a significant source of solar wind MHD turbulence intermittency. It has long been recognized that these structures can arise from non-linear interactions of MHD turbulence. Alternatively, they may also be relic structures in the solar wind that have a solar origin, e.g., magnetic walls of flux tubes that separate solar wind plasma into distinct parcels. Identifying these structures in the solar wind is crucial to understanding the properties of the solar wind MHD turbulence. Using Ulysses observations we examine 3-year worth of solar wind magnetic field data when the Ulysses is at low latitude during solar minimum. Extending the previous work of Li (2007, 2008), we develop an automatic data analysis method of current sheet identification. Using this method, we identify more than 28000 current sheets. Various properties of the current sheet are obtained. These include the distributions of the deflection angle across the current sheet, the thickness of the current sheet and the waiting time statistics between current sheets.

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