Density fluctuations in different types of solar wind flow at 1 AU and comparison with results from Doppler scintillation measurements near the Sun

<p>The solar wind aberration due to non-radial velocity components and the Earth orbital motion is important for the overall magnetosphere geometry because the magnetospheric tail is aligned with the solar wind flow. This paper investigates an evolution of non-radial components of the solar wind flow along the path from the Sun to 6 AU. A comparison of observations at 1 AU and closer to or further from the Sun based on measurements of many spacecraft at different locations in the heliosphere (Wind, ACE, Spektr-R, THEMIS B and C, Helios 1 and 2, Mars-Express, Voyager 1 and 2) shows that (i) the average values of non-radial components vary with the distance from the Sun and (ii) they differ according to solar wind streams.</p>

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Variations of flow direction in solar wind streams of different types

Solnechno-Zemnaya Fizika ◽

10.12737/szf-74202102 ◽

2021 ◽

Vol 7 (4) ◽

pp. 10-18

Author(s):

Anastasiya Moskaleva ◽

Mariya Ryazanceva ◽

Yuriy Ermolaev ◽

Irina Lodkina

Keyword(s):

Solar Wind ◽

High Speed ◽

Large Scale ◽

Weather Forecasting ◽

Flow Direction ◽

Coronal Holes ◽

Wind Flow ◽

Different Types ◽

Solar Wind Flow ◽

Spacecraft Data

Studying the direction of the solar wind flow is a topical problem of space weather forecasting. As a rule, the quiet and uniform solar wind propagates radially, but significant changes in the solar wind flow direction can be observed, for example, in compression regions before the interplanetary coronal mass ejections (Sheath) and Corotating Interaction Regions (CIR) that precede high-speed streams from coronal holes. In this study, we perform a statistical analysis of the longitude (φ) and latitude (θ) flow direction angles and their variations on different time scales (30 s and 3600 s) in solar wind large-scale streams of different types, using WIND spacecraft data. We also examine the relationships of the value and standard deviations SD of the flow direction angles with various solar wind parameters, regardless of the solar wind type. We have established that maximum values of longitude and latitude angle modulus, as well as their variations, are observed for Sheath, CIR, and Rare, with the probability of large deviations from the radial direction (>5°) increasing. The dependence on the solar wind type is shown to decrease with scale. We have also found that the probability of large values of SD(θ) and SD(φ) increases with increasing proton temperature (Tp) in the range 5–10 eV and with increasing proton velocity (Vp) in the range 400–500 km/s.

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Plasma processes at comet Churyumov–Gerasimenko: Expectations for Rosetta

Journal of Plasma Physics ◽

10.1017/s0022377813001116 ◽

2013 ◽

Vol 79 (6) ◽

pp. 1067-1070 ◽

Cited By ~ 1

Author(s):

D. A. MENDIS ◽

M. HORÁNYI

Keyword(s):

Solar Wind ◽

Solar Radiation ◽

Bow Shock ◽

Short Paper ◽

Wind Flow ◽

The Sun ◽

Cometary Plasma ◽

Variable Nature ◽

Solar Wind Flow ◽

Comet 67P

AbstractThe Rosetta–Philae mission to comet 67P/Churyumov–Gerasimenko in 2014 will provide a unique opportunity to observe the variable nature of the interaction of a comet with the solar radiation and the solar wind, as the comet approaches the Sun. In this short paper we will focus on the varying global structure of the cometary plasma environment. Specifically we make predictions on the varying locations of the two basic transitions in the global, contaminated solar wind flow toward the comet: the outer bow shock and the ionopause.

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Occurrence rate of magnetic holes between 0.72 and 1 AU: comparative study of Cluster and VEX data

Annales Geophysicae ◽

10.5194/angeo-29-717-2011 ◽

2011 ◽

Vol 29 (5) ◽

pp. 717-722 ◽

Cited By ~ 8

Author(s):

O. A. Amariutei ◽

S. N. Walker ◽

T. L. Zhang

Keyword(s):

Solar Wind ◽

Occurrence Rate ◽

Wind Flow ◽

The Sun ◽

Common Features ◽

The Earth ◽

Magnetic Field Magnitude ◽

Solar Wind Flow ◽

Stable Plasma ◽

The Magnetic Field

Abstract. Localised depressions in the magnetic field magnitude, or magnetic holes, are common features in many regions of solar system plasma. Two distinct mechanisms for their generation have been proposed. The first proposed that the structures are generated locally, close to the point of observation. The alternative has been proposed by Russell et al. (2008), who suggest that the observed magnetic holes represent nonlinear mirror structures that can be carried by the solar wind over vast distances of mirror stable plasma. According to Russell et al. (2008), magnetic holes are created in the vicinity of the sun and are convected by the solar wind outward. Periods of Cluster 1 and VEX data when both spacecraft were connected by the solar wind flow have been considered in this study, in order to determine the evolution of the magnetic holes occurrence rate. The comparison of the magnetic holes occurrence near the Venus and the Earth supports the Russell et al. (2008) premise that they are generated closer to the Sun most likely somewhere within the orbit of Mercury.

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Modelling the evolution of CMEs and their shocks through different solar wind structures

10.5194/egusphere-egu2020-11003 ◽

2020 ◽

Author(s):

Erika Palmerio ◽

Christina Lee ◽

Leila Mays ◽

Dusan Odstrcil

Keyword(s):

Magnetic Field ◽

Solar Wind ◽

Vantage Point ◽

Angular Width ◽

Wind Flow ◽

The Sun ◽

Ambient Wind ◽

Fast Wind ◽

Solar Wind Flow ◽

Ambient Solar Wind

<p>The evolution of coronal mass ejections (CMEs) as they travel away from the Sun is one of the major issues in heliophysics and space weather. After erupting, CMEs propagate outwards through the background solar wind flow, which in turn may significantly affect CME evolution by means of e.g. acceleration, deflection, and/or rotation. In order to determine to which extent the ambient wind can alter the speed, trajectory, and orientation of a CME, we run a series of 3D magnetohydrodynamics simulations (using the coupled solar&#8211;heliospheric WSA&#8211;Enlil model) to conduct a multi-vantage point study of the radial and longitudinal evolution of CME structures as they propagate up to Earth&#8217;s (1 AU) and Mars&#8217; (1.5 AU) orbits. We explore a broad range of input CME parameters (initial radial speed, angular width) and ambient solar wind conditions (slow versus fast wind) to investigate the different evolutionary behaviours of CMEs and their driven shocks and sheath regions. To study the radial and longitudinal evolution for the modelled CME ejecta and shock events, we examine the resulting magnetic field and plasma time series at different heliocentric distances (0.5 AU, 1 AU, and 1.5 AU) and heliolongitudes (in 30&#176; increments). This work will help establish a set of expected CME behaviours at Earth&#8217;s and Mars&#8217; radial distances, which can be used for analysing real CME events.</p>

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Variations of flow direction in solar wind streams of different types

Solar-Terrestrial Physics ◽

10.12737/stp-74202102 ◽

2021 ◽

Vol 7 (4) ◽

pp. 10-17

Author(s):

Anastasiya Moskaleva ◽

Mariya Ryazanceva ◽

Yuriy Ermolaev ◽

Irina Lodkina

Keyword(s):

Solar Wind ◽

High Speed ◽

Large Scale ◽

Weather Forecasting ◽

Flow Direction ◽

Coronal Holes ◽

Wind Flow ◽

Different Types ◽

Solar Wind Flow ◽

Spacecraft Data

Studying the direction of the solar wind flow is a topical problem of space weather forecasting. As a rule, the quiet and uniform solar wind propagates radially, but significant changes in the solar wind flow direction can be observed, for example, in compression regions before the interplanetary coronal mass ejections (Sheath) and Corotating Interaction Regions (CIR) that precede high-speed streams from coronal holes. In this study, we perform a statistical analysis of the longitude (φ) and latitude (θ) flow direction angles and their variations on different time scales (30 s and 3600 s) in solar wind large-scale streams of different types, using WIND spacecraft data. We also examine the relationships of the value and standard deviations SD of the flow direction angles with various solar wind parameters, regardless of the solar wind type. We have established that maximum values of longitude and latitude angle modulus, as well as their variations, are observed for Sheath, CIR, and Rare, with the probability of large deviations from the radial direction (>5°) increasing. The dependence on the solar wind type is shown to decrease with scale. We have also found that the probability of large values of SD(θ) and SD(φ) increases with increasing proton temperature (Tp) in the range 5–10 eV and with increasing proton velocity (Vp) in the range 400–500 km/s.

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