An Adaptive Prediction System for Specifying Solar Wind Conditions Near the Sun

2020 ◽  
Author(s):  
Martin Reiss ◽  
Peter MacNeice ◽  
Karin Muglach ◽  
Nick Arge ◽  
Christian Möstl ◽  
...  
Keyword(s):  
Solar Wind ◽  
Space Weather ◽  
Large Scale ◽  
Numerical Models ◽  
The Sun ◽  
Prediction System ◽  
Adaptive Prediction ◽  
Scientific Goal ◽  
Scale Properties ◽  
Weather Research

<p><span>The ambient solar wind flows and fields influence the complex propagation dynamics of coronal mass ejections in the interplanetary medium and play an essential role in shaping Earth's space weather environment. A critical scientific goal in the space weather research and prediction community is to develop, implement and optimize numerical models for specifying the large-scale properties of solar wind conditions at the inner boundary of the heliospheric model domain. Here we present an adaptive prediction system that fuses information from in situ measurements of the solar wind into numerical models to better match the global solar wind model solutions near the Sun with prevailing physical conditions in the vicinity of Earth. In this way, we attempt to advance the predictive capabilities of well-established solar wind models such as the Wang-Sheeley-Arge model. We perform a statistical analysis of the resulting solar wind predictions for the years 2006 to 2015. The proposed prediction scheme improves all the coronal/heliospheric model combinations investigated by approximately 15-20 percent in terms of various comprehensive prediction validation measures. We discuss why this is the case, and conclude that our findings have important implications for future practice in applied space weather research and prediction.</span></p>

scholarly journals Forecasting the Ambient Solar Wind with Numerical Models. II. An Adaptive Prediction System for Specifying Solar Wind Speed near the Sun

2020 ◽  
Vol 891 (2) ◽  
pp. 165 ◽  
Author(s):  
Martin A. Reiss ◽  
Peter J. MacNeice ◽  
Karin Muglach ◽  
Charles N. Arge ◽  
Christian Möstl ◽  
...  
Keyword(s):  
Solar Wind ◽  
Wind Speed ◽  
Numerical Models ◽  
Solar Wind Speed ◽  
The Sun ◽  
Prediction System ◽  
Adaptive Prediction ◽  
Ambient Solar Wind

scholarly journals Solar cycle changes of large-scale solar wind structure

2009 ◽  
Vol 5 (S264) ◽  
pp. 356-358 ◽  
Author(s):  
P. K. Manoharan
Keyword(s):  
Solar Wind ◽  
Solar Cycle ◽  
Large Scale ◽  
Interplanetary Space ◽  
The Sun ◽  
Wind Structure ◽  
Level Of Activity ◽  
Solar Wind Structure ◽  
Current Minimum ◽  
Inner Heliosphere

AbstractIn this paper, I present the results on large-scale evolution of density turbulence of solar wind in the inner heliosphere during 1985–2009. At a given distance from the Sun, the density turbulence is maximum around the maximum phase of the solar cycle and it reduces to ~70%, near the minimum phase. However, in the current minimum of solar activity, the level of turbulence has gradually decreased, starting from the year 2005, to the present level of ~30%. These results suggest that the source of solar wind changes globally, with the important implication that the supply of mass and energy from the Sun to the interplanetary space has significantly reduced in the present low level of activity.

scholarly journals The frequency of stellar X-ray flares from a large-scale XMM-Newton sample

2015 ◽  
Vol 11 (S320) ◽  
pp. 134-137
Author(s):  
John P. Pye ◽  
Simon R. Rosen
Keyword(s):  
Solar System ◽  
Solar Flare ◽  
Space Weather ◽  
White Light ◽  
Large Scale ◽  
The Sun ◽  
X Ray ◽  
Cool Star ◽  
Exoplanetary Systems ◽  
Solar Type

AbstractWe present estimates of cool-star X-ray flare rates determined from the XMM-Tycho survey (Pyeet al. 2015, A&A, 581, A28), and compare them with previously published values for the Sun and for other stellar EUV and white-light samples. We demonstrate the importance of applying appropriate corrections, especially in regard to the total, effective size of the stellar sample. Our results are broadly consistent with rates reported in the literature for Kepler white-light flares from solar-type stars, and with extrapolations of solar flare rates, indicating the potential of stellar X-ray flare observations to address issues such as ‘space weather’ in exoplanetary systems and our own solar system.

3D MHD study of the Earth magnetosphere response during extreme space weather conditions

2021 ◽  
Author(s):  
Jacobo Varela Rodriguez ◽  
Sacha A. Brun ◽  
Antoine Strugarek ◽  
Victor Réville ◽  
Filippo Pantellini ◽  
...  
Keyword(s):  
Solar Wind ◽  
Space Weather ◽  
Coronal Mass Ejections ◽  
Main Sequence ◽  
Dynamic Pressure ◽  
Weather Conditions ◽  
The Sun ◽  
Earth Surface ◽  
The Earth ◽  
The Imf

<p><span>The aim of the study is to analyze the response of the Earth magnetosphere for various space weather conditions and model the effect of interplanetary coronal mass ejections. The magnetopause stand off distance, open-closed field lines boundary and plasma flows towards the planet surface are investigated. We use the MHD code PLUTO in spherical coordinates to perform a parametric study regarding the dynamic pressure and temperature of the solar wind as well as the interplanetary magnetic field intensity and orientation. The range of the parameters analyzed extends from regular to extreme space weather conditions consistent with coronal mass ejections at the Earth orbit. The direct precipitation of the solar wind on the Earth day side at equatorial latitudes is extremely unlikely even during super coronal mass ejections. For example, the SW precipitation towards the Earth surface for a IMF purely oriented in the Southward direction requires a IMF intensity around 1000 nT and the SW dynamic pressure above 350 nPa, space weather conditions well above super-ICMEs. The analysis is extended to previous stages of the solar evolution considering the rotation tracks from Carolan (2019). The simulations performed indicate an efficient shielding of the Earth surface 1100 Myr after the Sun enters in the main sequence. On the other hand, for early evolution phases along the Sun main sequence once the Sun rotation rate was at least 5 times faster (< 440 Myr), the Earth surface was directly exposed to the solar wind during coronal mass ejections (assuming today´s Earth magnetic field). Regarding the satellites orbiting the Earth, Southward and Ecliptic IMF orientations are particularly adverse for Geosynchronous satellites, partially exposed to the SW if the SW dynamic pressure is 8-14 nPa and the IMF intensity 10 nT. On the other hand, Medium orbit satellites at 20000 km are directly exposed to the SW during Common ICME if the IMF orientation is Southward and during Strong ICME if the IMF orientation is Earth-Sun or Ecliptic. The same way, Medium orbit satellites at 10000 km are directly exposed to the SW if a Super ICME with Southward IMF orientation impacts the Earth.</span></p><p>This work was supported by the project 2019-T1/AMB-13648 founded by the Comunidad de Madrid, grants ERC WholeSun, Exoplanets A and PNP. We extend our thanks to CNES for Solar Orbiter, PLATO and Meteo Space science support and to INSU/PNST for their financial support.</p>

The Sun

2015 ◽  
Author(s):  
Joanna D. Haigh ◽  
Peter Cargill
Keyword(s):  
Magnetic Field ◽  
Solar Wind ◽  
Solar Atmosphere ◽  
Space Weather ◽  
Extreme Ultraviolet ◽  
The Sun ◽  
Base Level ◽  
Earth’S Climate ◽  
The Magnetic Field ◽  
Terrestrial Magnetic Field

This chapter discusses how there are four general factors that contribute to the Sun's potential role in variations in the Earth's climate. First, the fusion processes in the solar core determine the solar luminosity and hence the base level of radiation impinging on the Earth. Second, the presence of the solar magnetic field leads to radiation at ultraviolet (UV), extreme ultraviolet (EUV), and X-ray wavelengths which can affect certain layers of the atmosphere. Third, the variability of the magnetic field over a 22-year cycle leads to significant changes in the radiative output at some wavelengths. Finally, the interplanetary manifestation of the outer solar atmosphere (the solar wind) interacts with the terrestrial magnetic field, leading to effects commonly called space weather.

scholarly journals Interplanetary Disturbances Affecting Space Weather

2013 ◽  
Vol 8 (S300) ◽  
pp. 297-306 ◽  
Author(s):  
Robert F. Wimmer-Schweingruber
Keyword(s):  
Space Weather ◽  
Large Scale ◽  
Interplanetary Medium ◽  
Coronal Holes ◽  
Historical Review ◽  
The Sun ◽  
High Speeds ◽  
Large Scale Disturbance ◽  
Mass Ejection ◽  
Very High

AbstractThe Sun somehow accelerates the solar wind, an incessant stream of plasma originating in coronal holes and some, as yet unidentified, regions. Occasionally, coronal, and possibly sub-photospheric structures, conspire to energize a spectacular eruption from the Sun which we call a coronal mass ejection (CME). These can leave the Sun at very high speeds and travel through the interplanetary medium, resulting in a large-scale disturbance of the ambient background plasma. These interplanetary CMEs (ICMEs) can drive shocks which in turn accelerate particles, but also have a distinct intrinsic magnetic structure which is capable of disturbing the Earth's magnetic field and causing significant geomagnetic effects. They also affect other planets, so they can and do contribute to space weather throughout the heliosphere. This paper presents a historical review of early space weather studies, a modern-day example, and discusses space weather throughout the heliosphere.

Large-scale solar-wind structure near the Sun detected by Doppler scintillation

Nature ◽  
1993 ◽  
Vol 366 (6455) ◽  
pp. 543-545 ◽  
Author(s):  
Richard Woo ◽  
Paul Gazis
Keyword(s):  
Solar Wind ◽  
Large Scale ◽  
The Sun ◽  
Wind Structure ◽  
Solar Wind Structure

Large-scale electron solar wind parameters of the inner heliosphere with Parker Solar Probe/FIELDS

2020 ◽  
Author(s):  
Karine Issautier ◽  
Mingzhe Liu ◽  
Michel Moncuquet ◽  
Nicole Meyer-Vernet ◽  
Milan Maksimovic ◽  
...  
Keyword(s):  
Solar Wind ◽  
Large Scale ◽  
Statistical Study ◽  
Solar Wind Speed ◽  
The Sun ◽  
Solar Wind Parameters ◽  
Power Law Index ◽  
Probe Mission ◽  
Inner Heliosphere

<p>We present in situ properties of electron density and temperature in the inner heliosphere obtained during the three first solar encounters at 35 solar radii of the Parker Solar Probe mission. These preliminary results, recently shown by Moncuquet et al., ApJS, 2020, are obtained from the analysis of the plasma quasi-thermal noise (QTN) spectrum measured by the radio RFS/FIELDS instrument along the trajectories extending between 0.5 and 0.17 UA from the Sun, revealing different states of the emerging solar wind, five months apart. The temperature of the weakly collisional core population varies radially with a power law index of about -0.8, much slower than adiabatic, whereas the temperature of the supra-thermal population exhibits a much flatter radial variation, as expected from its nearly collisionless state. These measured temperatures are close to extrapolations towards the Sun of Helios measurements.</p><p>We also present a statistical study from these in situ electron solar wind parameters, deduced by QTN spectroscopy, and compare the data to other onboard measurements. In addition, we focus on the large-scale solar wind properties. In particular, from the invariance of the energy flux, a direct relation between the solar wind speed and its density can be deduced, as we have already obtained based on Wind continuous in situ measurements (Le Chat et al., Solar Phys., 2012). We study this anti-correlation during the three first solar encounters of PSP.</p>

scholarly journals The solar wind angular-momentum flux observed during Solar Orbiter's first orbit

2021 ◽  
Author(s):  
Daniel Verscharen ◽  
David Stansby ◽  
Adam Finley ◽  
Christopher Owen ◽  
Timothy Horbury ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Solar Wind ◽  
Angular Momentum ◽  
Momentum Flux ◽  
Large Scale ◽  
Magnetic Field Data ◽  
Proton Data ◽  
Scale Properties ◽  
Orbiter Mission

<p>The Solar Orbiter mission is currently in its cruise phase, during which the spacecraft's in-situ instrumentation measures the solar wind and the electromagnetic fields at different heliocentric distances. </p><p>We evaluate the solar wind angular-momentum flux by combining proton data from the Solar Wind Analyser (SWA) Proton-Alpha Sensor (PAS) and magnetic-field data from the Magnetometer (MAG) instruments on board Solar Orbiter during its first orbit. This allows us to evaluate the angular momentum in the protons in addition to that stored in magnetic-field stresses, and compare these to previous observations from other spacecraft. We discuss the statistical properties of the angular-momentum flux and its dependence on solar-wind properties. </p><p>Our results largely agree with previous measurements of the solar wind’s angular-momentum flux in the inner heliosphere and demonstrate the potential for future detailed studies of large-scale properties of the solar wind with the data from Solar Orbiter.</p>

scholarly journals The influence of solar wind turbulence on geomagnetic activity

2008 ◽  
Vol 15 (1) ◽  
pp. 53-59 ◽  
Author(s):  
D. Jankovičovà ◽  
Z. Vörös ◽  
J. Šimkanin
Keyword(s):  
Magnetic Field ◽  
Solar Wind ◽  
Magnetic Reconnection ◽  
Interplanetary Magnetic Field ◽  
Space Weather ◽  
Coupled System ◽  
Statistical Moment ◽  
The Sun ◽  
H Index ◽  
Magnetic Turbulence

Abstract. The importance of space weather and its forecasting is growing as interest in studying geoeffective processes in the Sun – solar wind – magnetosphere – ionosphere coupled system is increasing. In this paper higher order statistical moments of interplanetary magnetic field and geomagnetic SYM-H index fluctuations are compared. The proper description of fluctuations in the solar wind can elucidate important aspects of the geoeffectivity of upstream turbulence and contribute to our understanding of space weather. Our results indicate that quasi-stationary intervals during both quiet and stormy periods have to be investigated in order to find correlations between upstream and geomagnetic conditions. We found that the fourth statistical moment (kurtosis), which was not considered in previous studies, appears to be a new geoeffective parameter. Intermittency of the magnetic turbulence in the solar wind can influence the efficiency of the solar wind – magnetosphere coupling through affecting magnetic reconnection at the Earth's magnetopause.

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