Manifestations of the ray structure of the coronal streamer belt in the form of sharp peaks of the solar wind plasma density in the Earth’s orbit

2006 ◽  
Vol 46 (6) ◽  
pp. 770-782 ◽  
Author(s):  
M. V. Eselevich ◽  
V. G. Eselevich
Keyword(s):  
Solar Wind ◽  
Plasma Density ◽  
Solar Wind Plasma ◽  
Streamer Belt ◽  
Coronal Streamer

scholarly journals Three-dimensional multi-fluid model of a coronal streamer belt with a tilted magnetic dipole

2015 ◽  
Vol 33 (1) ◽  
pp. 47-53 ◽  
Author(s):  
L. Ofman ◽  
E. Provornikova ◽  
L. Abbo ◽  
S. Giordano
Keyword(s):  
Solar Wind ◽  
Heavy Ions ◽  
Fluid Model ◽  
Slow Solar Wind ◽  
Streamer Belt ◽  
Lower Corona ◽  
Adequate Model ◽  
Coronal Streamer ◽  
Ion Emission ◽  
D Model

Abstract. Observations of streamers in extreme ultraviolet (EUV) emission with SOHO/UVCS show dramatic differences in line profiles and latitudinal variations in heavy ion emission compared to hydrogen Ly-α emission. In order to use ion emission observations of streamers as the diagnostics of the slow solar wind properties, an adequate model of a streamer including heavy ions is required. We extended a previous 2.5-D multi-species magnetohydrodynamics (MHD) model of a coronal streamer to 3-D spherical geometry, and in the first approach we consider a tilted dipole configuration of the solar magnetic field. The aim of the present study is to test the 3-D results by comparing to previous 2.5-D model result for a 3-D case with moderate departure from azimuthal symmetry. The model includes O5+ ions with preferential empirical heating and allows for calculation of their density, velocity and temperature in coronal streamers. We present the first results of our 3-D multi-fluid model showing the parameters of protons, electrons and heavy ions (O5+) at the steady-state solar corona with a tilted steamer belt. We find that the 3-D results are in qualitative agreement with our previous 2.5-D model, and show longitudinal variation in the variables in accordance with the tilted streamer belt structure. Properties of heavy coronal ions obtained from the 3-D model together with EUV spectroscopic observations of streamers will help understanding the 3-D structures of streamers reducing line-of-sight integration ambiguities and identifying the sources of the slow solar wind in the lower corona. This leads to improved understanding of the physics of the slow solar wind.

scholarly journals Coronal streamer belt asymmetries and seasonal solar wind variations deduced from Wind and Ulysses data

1997 ◽  
Vol 102 (A3) ◽  
pp. 4673-4679 ◽  
Author(s):  
N. U. Crooker ◽  
A. J. Lazarus ◽  
J. L. Phillips ◽  
J. T. Steinberg ◽  
A. Szabo ◽  
...  
Keyword(s):  
Solar Wind ◽  
Streamer Belt ◽  
Coronal Streamer

scholarly journals Diamagnetic structures as a basis of quasi-stationary slow solar wind

2019 ◽  
Vol 5 (3) ◽  
pp. 36-49
Author(s):  
Виктор Еселевич ◽  
Viktor Eselevich
Keyword(s):  
Magnetic Field ◽  
Solar Wind ◽  
Plasma Density ◽  
Neutral Line ◽  
Angular Size ◽  
Radial Component ◽  
Slow Solar Wind ◽  
Small Scale ◽  
The Sun ◽  
Streamer Belt

The results presented in this review reflect the fundamentals of the modern understanding of the nature of the structure of the slow solar wind (SW) along the entire length from the Sun to the Earth's orbit. It is known that the source of the slow quasi-stationary SW on the Sun is the belt and the chains of coronal streamers The streamer belt encircles the entire Sun as a wave-like surface (skirt), representing a sequence of pairs of rays with increased brightness (plasma density) or two lines of rays located close to each other. Neutral line of the radial component of the solar global magnetic field goes along the belt between the rays of each of these pairs. The streamer belt extends in the heliosphere is as the heliospheric plasma sheet (HPS). Detailed analysis of data from Wind and IMP-8 satellites showed that HPS sections on the Earth orbit are registered as a sequence of diamagnetic tubes with high density plasma and low interplanetary magnetic field. They represent an extension of rays with increased brightness of the streamer belt near the Sun. Their angular size remains the same over the entire way from the Sun to the Earth's orbit. Each HPS diamagnetic tube has a fine internal structure on several scales, or fractality. In other words, diamagnetic tube is a set of nested diamagnetic tubes, whose angular size can vary by almost two orders of magnitude. These sequences of diamagnetic tubes that form the base of slow SW on the Earth's orbit has a more general name — diamagnetic structures (DS). In the final part of this article, a comparative analysis of several events was made, based on the results of this review. He made it possible to find out the morphology and nature of the origin of the new term “diamagnetic plasmoids” SW (local amplifications of plasma density), which appeared in several articles published during 2012–2018. The analysis carried out at the end of this article, for the first time, showed that the diamagnetic plasmoids SW are the small-scale component of the fractal diamagnetic structures of the slow SW, considered in this review.

scholarly journals Oxygen abundance in coronal streamers during solar minimum

2001 ◽  
Vol 19 (2) ◽  
pp. 135-145 ◽  
Author(s):  
D. Marocchi ◽  
E. Antonucci ◽  
S. Giordano
Keyword(s):  
Solar Wind ◽  
Solar Minimum ◽  
Ultra Violet ◽  
Solar Wind Plasma ◽  
Slow Solar Wind ◽  
Streamer Belt ◽  
Oxygen Abundance ◽  
The Core ◽  
Interplanetary Physics ◽  
Slow Wind

Abstract. We present a study of the oxygen abundance relative to hydrogen in the equatorial streamer belt of the solar corona during the recent period of activity minimum. The oxygen abundance is derived from the spectroscopic observations of the outer corona performed during 1996 with the Ultraviolet Coronagraph Spectrometer (SOHO) in the ultra-violet region. This study shows that the depletion of oxygen, by almost one order of magnitude with respect to the photospheric values, found in the inner part of streamers by Raymond et al. (1997a) is a common feature of the solar minimum streamer belt, which exhibits an abundance structure with the following characteristics. In the core of streamers the oxygen abundance is 1.3 × 10-4 at 1.5 R⊙, then it drops to 0.8 × 10-4 at 1.7 R⊙, value which remains almost constant out to 2.2 R⊙. In the lateral bright structures that are ob-served to surround the core of streamers in the oxygen emission, the oxygen abundance drops monotonically with heliodistance, from 3.5 × 10-4 at 1.5 R⊙ to 2.2 × 10-4 at 2.2 R⊙. The oxygen abundance structure found in the streamer belt is consistent with the model of magnetic topology of streamers proposed by Noci et al. (1997). The composition of the plasma contained in streamers is not the same as observed in the slow solar wind. Even in the lateral branches, richer in oxygen, at 2.2 R⊙ the abundance drops by a factor 2 with respect to the slow wind plasma observed with Ulysses during the declining phase of the solar cycle. Hence the slow wind does not appear to originate primarily from streamers, with the exception perhaps of the plasma flowing along the heliospheric current sheet.Key words. Interplanetary physics (solar wind plasma) – Solar physics, astrophysics and astronomy (corona and transition region; ultraviolet emissions)

scholarly journals Daily Variations of Plasma Density in the Solar Streamer Belt

2021 ◽  
Vol 922 (2) ◽  
pp. 165
Author(s):  
Huw Morgan
Keyword(s):  
Magnetic Field ◽  
Solar Wind ◽  
Plasma Density ◽  
Time Lag ◽  
Propagation Speed ◽  
Variable Density ◽  
Field Variable ◽  
Slow Solar Wind ◽  
Streamer Belt ◽  
Wind Variability

Abstract Improved space weather diagnostics depend critically on improving our understanding of the evolution of the slow solar wind in the streamer belts near the Sun. Recent innovations in tomography techniques are opening a new window on this complex environment. In this work, a new time-dependent technique is applied to COR2A/Solar Terrestrial Relations Observatory observations from a period near solar minimum (2018 November 11) for heliocentric distances of 4–8 R ⊙. For the first time, we find density variations of large amplitude throughout the quiescent streamer belt, ranging between 50% and 150% of the mean density, on timescales of tens of hours to days. Good agreement is found with Parker Solar Probe measurements at perihelion; thus, the variations revealed by tomography must form a major component of the slow solar wind variability, distinct from coronal mass ejections or smaller transients. A comparison of time series at different heights reveals a consistent time lag, so that changes at 4 R ⊙ occur later at increasing height, corresponding to an outward propagation speed of around 100 km s−1. This speed may correspond to either the plasma sound speed or the bulk outflow speed depending on an important question: are the density variations caused by the spatial movement of a narrow streamer belt (moving magnetic field, constant plasma density), or changes in plasma density within a nonmoving streamer belt (rigid magnetic field, variable density), or a combination of both?

scholarly journals Solar Wind Plasma Properties During Ortho-Parker IMF Conditions and Associated Magnetosheath Mirror Instability Response

2021 ◽  
Vol 8 ◽  
Author(s):  
V. Génot ◽  
B. Lavraud
Keyword(s):  
Magnetic Field ◽  
Solar Wind ◽  
Solar Wind Plasma ◽  
Streamer Belt ◽  
Plasma Properties ◽  
Parker Spiral ◽  
Mirror Mode ◽  
Categorization Scheme ◽  
The Stability ◽  
Region Plasma

The properties of the solar wind fraction that exhibits an Interplanetary Magnetic Field (IMF) orientation orthogonal to the classical Parker spiral (so-called ortho-Parker) are investigated. We make use of a solar wind plasma categorization scheme, using 10 years of OMNI data, and show that the fractions of the different plasma origins (streamer-belt-origin plasma, coronal-hole-origin plasma, sector-reversal-region plasma and ejecta) identified by this scheme are rather constant when expressed as a function of the IMF orientation whereas the Alfvén Mach number significantly depends on this orientation. This has direct implication on the magnetosheath dynamics and, as an example, the stability of the mirror mode in this compressed plasma is studied thanks to Rankine-Hugoniot anisotropic relations. This study sheds light on previously reported, yet unexplained, observations of a larger occurrence of mirror mode in the magnetosheath downstream of ortho-Parker IMF.

scholarly journals The solar wind plasma density control of night-time auroral particle precipitation

2004 ◽  
Vol 22 (3) ◽  
pp. 1047-1052 ◽  
Author(s):  
V. G. Vorobjev ◽  
B. V. Rezhenov ◽  
O. I. Yagodkina
Keyword(s):  
Solar Wind ◽  
Plasma Density ◽  
Plasma Sheet ◽  
Solar Wind Plasma ◽  
Ion Flux ◽  
Night Time ◽  
Particle Precipitation ◽  
Ion Energy ◽  
Flux Enhancement ◽  
Density Control

Abstract. DMSP F6 and F7 spacecraft observations of the average electron and ion energy, and energy fluxes in different night-time precipitation regions for the whole of 1986 were used to examine the precipitation features associated with solar wind density changes. It was found that during magnetic quietness |AL|<100nT), the enhancement of average ion fluxes was observed at least two times, along with the solar wind plasma density increase from 2 to 24cm–3. More pronounced was the ion flux enhancement that occurred in the b2i–b4s and b4s–b5 regions, which are approximately corresponding to the statistical auroral oval and map to the magnetospheric plasma sheet tailward of the isotropy boundary. The average ion energy decrease of about 2–4kev was registered simultaneously with this ion flux enhancement. The results verify the occurrence of effective penetration of the solar wind plasma into the magnetospheric tail plasma sheet. Key words. Ionosphere (auroral ionosphere, particle precipitation) – Magnetospheric physics (solar windmagnetosphere interaction)

scholarly journals Diamagnetic structures as a basis of quasi-stationary slow solar wind

2019 ◽  
Vol 5 (3) ◽  
pp. 29-41 ◽  
Author(s):  
Виктор Еселевич ◽  
Viktor Eselevich
Keyword(s):  
Magnetic Field ◽  
Solar Wind ◽  
Plasma Density ◽  
Neutral Line ◽  
Angular Size ◽  
Radial Component ◽  
Slow Solar Wind ◽  
Small Scale ◽  
The Sun ◽  
Streamer Belt

The results presented in this review reflect the fundamentals of the modern understanding of the nature of the structure of the slow solar wind (SW) along the entire length from the Sun to the Earth's orbit. It is known that the source of the slow quasi-stationary SW on the Sun is the belt and the chains of coronal streamers The streamer belt encircles the entire Sun as a wave-like surface (skirt), representing a sequence of pairs of rays with increased brightness (plasma density) or two lines of rays located close to each other. Neutral line of the radial component of the solar global magnetic field goes along the belt between the rays of each of these pairs. The streamer belt extends in the heliosphere is as the heliospheric plasma sheet (HPS). Detailed analysis of data from Wind and IMP-8 satellites showed that HPS sections on the Earth orbit are registered as a sequence of diamagnetic tubes with high density plasma and low interplanetary magnetic field. They represent an extension of rays with increased brightness of the streamer belt near the Sun. Their angular size remains the same over the entire way from the Sun to the Earth's orbit. Each HPS diamagnetic tube has a fine internal structure on several scales, or fractality. In other words, diamagnetic tube is a set of nested diamagnetic tubes, whose angular size can vary by almost two orders of magnitude. These sequences of diamagnetic tubes that form the base of slow SW on the Earth's orbit has a more general name — diamagnetic structures (DS). In the final part of this article, a comparative analysis of several events was made, based on the results of this review. He made it possible to find out the morphology and nature of the origin of the new term “diamagnetic plasmoids” SW (local amplifications of plasma density), which appeared in several articles published during 2012–2018. The analysis carried out at the end of this article, for the first time, showed that the diamagnetic plasmoids SW are the small-scale component of the fractal diamagnetic structures of the slow SW, considered in this review.

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