scholarly journals Solar wind from high-latitude coronal holes at solar maximum

2002 ◽  
Vol 29 (9) ◽  
pp. 28-1-28-4 ◽  
Author(s):  
D. J. McComas ◽  
H. A. Elliott ◽  
R. von Steiger
Keyword(s):  
Solar Wind ◽  
High Latitude ◽  
Solar Maximum ◽  
Coronal Holes

High-latitude observations of solar wind streams and coronal holes

1976 ◽  
Vol 81 (22) ◽  
pp. 3845-3850 ◽  
Author(s):  
B. J. Rickett ◽  
D. G. Sime ◽  
N. R. Sheeley ◽  
W. R. Crockett ◽  
R. Tousey
Keyword(s):  
Solar Wind ◽  
High Latitude ◽  
Coronal Holes

Correlation of high latitude coronal holes with solar wind streams far above or below the ecliptic

Solar Physics ◽  
1982 ◽  
Vol 78 (2) ◽  
pp. 365-372 ◽  
Author(s):  
Kile B. Baker ◽  
Michael D. Papagiannis
Keyword(s):  
Solar Wind ◽  
High Latitude ◽  
Coronal Holes

Recurrent high-speed solar wind co-rotating interaction region imprint on the ionosphere and atmosphere: GPS TEC variations and atmospheric gravity waves

2020 ◽  
Author(s):  
James M. Weygand ◽  
Paul Prikryl ◽  
Reza Ghoddousi-Fard ◽  
Lidia Nikitina ◽  
Bharat S. R. Kunduri
Keyword(s):  
Solar Wind ◽  
Gravity Waves ◽  
High Latitude ◽  
High Speed ◽  
Geomagnetic Storms ◽  
Coronal Holes ◽  
Lower Thermosphere ◽  
Ionospheric Currents ◽  
Atmospheric Gravity Waves ◽  
Atmospheric Gravity

<p>High-speed streams (HSS) from coronal holes dominate solar wind structure in the absence of coronal mass ejections during solar minimum and the descending branch of solar cycle. Prominent and long-lasting coronal holes produce intense co-rotating interaction regions (CIR) on the leading edge of high-speed plasma streams that cause recurrent ionospheric disturbances and geomagnetic storms. Through solar wind coupling to the magnetosphere-ionosphere-atmosphere (MIA) system they affect the ionosphere and neutral atmosphere at high latitudes, and, at mid to low latitudes, by the transmission of the electric fields [1] and propagation of atmospheric gravity waves from the high-latitude lower thermosphere [2].</p><p>The high-latitude ionospheric structure, caused by precipitation of energetic particles, strong ionospheric currents and convection, results in changes of the GPS total electron content (TEC) and rapid variations of GPS signal amplitude and phase, called scintillation [3]. The GPS phase scintillation is observed in the ionospheric cusp, polar cap and auroral zone, and is particularly intense during geomagnetic storms, substorms and auroral breakups. Phase scintillation index is computed for a sampling rate of 50 Hz by specialized GPS scintillation receivers from the Canadian High Arctic Ionospheric Network (CHAIN). A proxy index of phase variation is obtained from dual frequency measurements of geodetic-quality GPS receivers sampling at 1 Hz, which include globally distributed receivers of the RT-IGS network that are monitored by the Canadian Geodetic Survey in near-real-time [4]. Temporal and spatial changes of TEC and phase variations following the arrivals of HSS/CIRs [5] are investigated in the context of ionospheric convection and equivalent ionospheric currents derived from  a ground magnetometer network using the spherical elementary current system method [6,7].</p><p>The Joule heating and Lorentz forcing in the high-latitude lower thermosphere have long been recognized as sources of internal atmospheric gravity waves (AGWs) [2] that propagate both upward and downward, thus providing vertical coupling between atmospheric layers. In the ionosphere, they are observed as traveling ionospheric disturbances (TIDs) using various techniques, e.g., de-trended GPS TEC maps [8].</p><p>In this paper we examine the influence on the Earth’s ionosphere and atmosphere of a long-lasting HSS/CIRs from recurrent coronal holes at the end of solar cycles 23 and 24. The solar wind MIA coupling, as represented by the coupling function [9], was strongly increased during the arrivals of these HSS/CIRs.</p><p> </p><p>[1] Kikuchi, T. and K. K. Hashimoto, Geosci. Lett. , 3:4, 2016.</p><p>[2] Hocke, K. and K. Schlegel, Ann. Geophys., 14, 917–940, 1996.</p><p>[3] Prikryl, P., et al., J. Geophys. Res. Space Physics, 121, 10448–10465, 2016.</p><p>[4] Ghoddousi-Fard et al., Advances in Space Research, 52(8), 1397-1405, 2013.</p><p>[5] Prikryl et al. Earth, Planets and Space, 66:62, 2014.</p><p>[6] Amm O., and A. Viljanen, Earth Planets Space, 51, 431–440, 1999.</p><p>[7] Weygand J.M., et al., J. Geophys. Res., 116, A03305, 2011.</p><p>[8] Tsugawa T., et al., Geophys. Res. Lett., 34, L22101, 2007.</p><p>[9] Newell P. T., et al., J. Geophys. Res., 112, A01206, 2007.</p>

scholarly journals How did the solar wind structure change around the solar maximum? From interplanetary scintillation observation

2003 ◽  
Vol 21 (6) ◽  
pp. 1257-1261 ◽  
Author(s):  
K. Fujiki ◽  
M. Kojima ◽  
M. Tokumaru ◽  
T. Ohmi ◽  
A. Yokobe ◽  
...  
Keyword(s):  
Solar Wind ◽  
Northern Hemisphere ◽  
High Speed ◽  
Solar Maximum ◽  
Complex Structure ◽  
Coronal Holes ◽  
Interplanetary Scintillation ◽  
Wind Structure ◽  
Interplanetary Physics ◽  
Solar Wind Structure

Abstract. Observations from the second Ulysses fast latitude scan show that the global structure of solar wind near solar maximum is much more complex than at solar minimum. Soon after solar maximum, Ulysses observed a polar coronal hole (high speed) plasma with magnetic polarity of the new solar cycle in the Northern Hemisphere. We analyze the solar wind structure at and near solar maximum using interplanetary scintillation (IPS) measurements. To do this, we have developed a new tomographic technique, which improves our ability to examine the complex structure of the solar wind at solar maximum. Our IPS results show that in 1999 and 2000 the total area with speed greater than 700 km s-1 is significantly reduced first in the Northern Hemisphere and then in the Southern Hemisphere. For year 2001, we find that the formation of large areas of fast solar wind around the north pole precedes the formation of large polar coronal holes around the southern pole by several months. The IPS observations show a high level agreement to the Ulysses observation, particularly in coronal holes.Key words. Interplanetary physics (solar wind plasma) – Radio science (remote sensing)

scholarly journals Velocity fluctuations in polar solar wind: a comparison between different solar cycles

2009 ◽  
Vol 27 (2) ◽  
pp. 877-883 ◽  
Author(s):  
B. Bavassano ◽  
R. Bruno ◽  
R. D'Amicis
Keyword(s):  
Solar Wind ◽  
Wind Velocity ◽  
High Latitude ◽  
Coronal Holes ◽  
Dimensional Structure ◽  
Time Lags ◽  
Solar Cycles ◽  
Polar Wind ◽  
Activity Maximum ◽  
Velocity Fluctuations

Abstract. The polar solar wind is a fast, tenuous and steady flow that, with the exception of a relatively short phase around the Sun's activity maximum, fills the high-latitude heliosphere. The polar wind properties have been extensively investigated by Ulysses, the first spacecraft able to perform in-situ measurements in the high-latitude heliosphere. The out-of-ecliptic phases of Ulysses cover about seventeen years. This makes possible to study heliospheric properties at high latitudes in different solar cycles. In the present investigation we focus on hourly- to daily-scale fluctuations of the polar wind velocity. Though the polar wind is a quite uniform flow, fluctuations in its velocity do not appear negligible. A simple way to characterize wind velocity variations is that of performing a multi-scale statistical analysis of the wind velocity differences. Our analysis is based on the computation of velocity differences at different time lags and the evaluation of statistical quantities (mean, standard deviation, skewness, and kurtosis) for the different ensembles. The results clearly show that, though differences exist in the three-dimensional structure of the heliosphere between the investigated solar cycles, the velocity fluctuations in the core of polar coronal holes exhibit essentially unchanged statistical properties.

scholarly journals Variation of Solar Wind Parameters During Intense Geomagnetic Storms

2017 ◽  
pp. 80-85 ◽  
Author(s):  
Ayush Subedi ◽  
Binod Adhikari ◽  
Roshan Kumar Mishra
Keyword(s):  
Solar Wind ◽  
Geomagnetic Storms ◽  
Solar Maximum ◽  
Coronal Holes ◽  
Research Work ◽  
Energy Coupling ◽  
Solar Wind Plasma ◽  
Geomagnetic Disturbance ◽  
Strong Impact ◽  
Geomagnetic Disturbances

Geomagnetic disturbances are caused by enhanced solar wind magnetospheric energy coupling process. The principal cause of geomagnetic disturbance is the magnetic reconnection that establishes an electrodynamical coupling between the solar wind plasma and magnetosphere. Around solar maximum, the main structures emanating from the sun are sporadic Coronal Mass Ejection (CMEs) and their interplanetary counterparts (ICMEs). During the descending and minimum solar cycle phases, coronal holes occur more often. They appear as dark regions confined to Solar poles during the solar maximum but expand in size and moves toward the solar equator during the descending phase. In this work, we have taken three different geomagnetic storms during solar maxima. For the interpretation of events, we used interplanetary solar wind data and geomagnetic indices. These satellite data and Dst indices (ranging from -100nT to above) are interpreted by using the method of cross correlation. The values of Bz found approximately 20nT, -50nT and -20nT respectively. Similarly, the value of Dst is -250nT, -400nT and -300nT which shows very intense effect. Likewise, the correlation coefficient we obtained from this research work strongly suggest that interplanetary magnetic field Bz has strong impact for the cause of geomagnetic storms.The Himalayan Physics Vol. 6 & 7, April 2017 (80-85)

Relation of solar wind parameters to high-latitude magnetic pulsations

2006 ◽  
Vol 12 (1) ◽  
pp. 80-84
Author(s):  
S.N. Samsonov ◽  
◽  
I.Ya. Plotnikov ◽  
D.Y. Sibeck ◽  
Yu. Watermann ◽  
...  
Keyword(s):  
Solar Wind ◽  
High Latitude ◽  
Magnetic Pulsations ◽  
Solar Wind Parameters

scholarly journals The influence of solar wind on extratropical cyclones – Part 1: Wilcox effect revisited

2009 ◽  
Vol 27 (1) ◽  
pp. 1-30 ◽  
Author(s):  
P. Prikryl ◽  
V. Rušin ◽  
M. Rybanský
Keyword(s):  
Time Series ◽  
Solar Wind ◽  
Northern Hemisphere ◽  
High Speed ◽  
Coronal Holes ◽  
Extratropical Cyclones ◽  
Sector Boundary ◽  
Speed Solar Wind ◽  
The Mean ◽  
High Speed Solar Wind

Abstract. A sun-weather correlation, namely the link between solar magnetic sector boundary passage (SBP) by the Earth and upper-level tropospheric vorticity area index (VAI), that was found by Wilcox et al. (1974) and shown to be statistically significant by Hines and Halevy (1977) is revisited. A minimum in the VAI one day after SBP followed by an increase a few days later was observed. Using the ECMWF ERA-40 re-analysis dataset for the original period from 1963 to 1973 and extending it to 2002, we have verified what has become known as the "Wilcox effect" for the Northern as well as the Southern Hemisphere winters. The effect persists through years of high and low volcanic aerosol loading except for the Northern Hemisphere at 500 mb, when the VAI minimum is weak during the low aerosol years after 1973, particularly for sector boundaries associated with south-to-north reversals of the interplanetary magnetic field (IMF) BZ component. The "disappearance" of the Wilcox effect was found previously by Tinsley et al. (1994) who suggested that enhanced stratospheric volcanic aerosols and changes in air-earth current density are necessary conditions for the effect. The present results indicate that the Wilcox effect does not require high aerosol loading to be detected. The results are corroborated by a correlation with coronal holes where the fast solar wind originates. Ground-based measurements of the green coronal emission line (Fe XIV, 530.3 nm) are used in the superposed epoch analysis keyed by the times of sector boundary passage to show a one-to-one correspondence between the mean VAI variations and coronal holes. The VAI is modulated by high-speed solar wind streams with a delay of 1–2 days. The Fourier spectra of VAI time series show peaks at periods similar to those found in the solar corona and solar wind time series. In the modulation of VAI by solar wind the IMF BZ seems to control the phase of the Wilcox effect and the depth of the VAI minimum. The mean VAI response to SBP associated with the north-to-south reversal of BZ is leading by up to 2 days the mean VAI response to SBP associated with the south-to-north reversal of BZ. For the latter, less geoeffective events, the VAI minimum deepens (with the above exception of the Northern Hemisphere low-aerosol 500-mb VAI) and the VAI maximum is delayed. The phase shift between the mean VAI responses obtained for these two subsets of SBP events may explain the reduced amplitude of the overall Wilcox effect. In a companion paper, Prikryl et al. (2009) propose a new mechanism to explain the Wilcox effect, namely that solar-wind-generated auroral atmospheric gravity waves (AGWs) influence the growth of extratropical cyclones. It is also observed that severe extratropical storms, explosive cyclogenesis and significant sea level pressure deepenings of extratropical storms tend to occur within a few days of the arrival of high-speed solar wind. These observations are discussed in the context of the proposed AGW mechanism as well as the previously suggested atmospheric electrical current (AEC) model (Tinsley et al., 1994), which requires the presence of stratospheric aerosols for a significant (Wilcox) effect.

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