MAGNETIC CLOUDS: A SUBJECT OF SPACE WEATHER PREDICTION

2005 ◽  
Vol 20 (29) ◽  
pp. 6650-6653
Author(s):  
A. GERANIOS ◽  
M. VANDAS ◽  
E. ANTONIADOU ◽  
O. ZACHAROPOULOU

Magnetic clouds are ideal objects for solar-terrestrial studies because of their simplicity and their extended time intervals of southward and northward magnetic fields. Magnetic clouds constitute a significant subset of coronal mass ejections with remarkable characteristics in the interplanetary medium and a strong influence on the Earth's magnetosphere, giving rise to geomagnetic storms. The evolution of such a cloud from the neighborhood of the Sun up to the Earth is numerically simulated for two cases, without and with a presence of a faster moving shock front. Its influence on the magnetosphere can be seen by the triggered geomagnetic storm. Therefore, magnetic clouds are an important subject for space weather predictions.

Author(s):  
Joanna D. Haigh ◽  
Peter Cargill

This chapter focuses on the link between Sun and Earth generically known as space weather. This link is referred to as the occurrence in the solar corona of energetic phenomenon such as flares and coronal mass ejections which can have a major impact on the Earth's space environment. There were other discoveries in subsequent years, but the 1950s and 1960s brought major advances in the understanding of the connection between the Sun and the Earth. Satellite observations confirmed the existence of the solar wind, so that the nature of the interplanetary medium was identified and measured. Such continuous monitoring of the Sun and solar wind has, in turn, led to methods for predicting deleterious space weather.


2021 ◽  
Author(s):  
Jacobo Varela Rodriguez ◽  
Sacha A. Brun ◽  
Antoine Strugarek ◽  
Victor Réville ◽  
Filippo Pantellini ◽  
...  

<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>


2018 ◽  
Vol 13 (S340) ◽  
pp. 83-84
Author(s):  
Kunjal Dave ◽  
Wageesh Mishra ◽  
Nandita Srivastava ◽  
R. M. Jadhav

AbstractIt has been established that Coronal Mass Ejections (CMEs) may have significant impact on terrestrial magnetic field and lead to space weather events. In the present study, we selected several CMEs which are associated with filament eruptions on the Sun. We attempt to identify the presence of filament material within ICME at 1AU. We discuss how different ICMEs associated with filaments lead to moderate or major geomagnetic activity on their arrival at the Earth. Our study also highlights the difficulties in identifying the filament material at 1AU within isolated and in interacting CMEs.


2011 ◽  
Vol 7 (S286) ◽  
pp. 242-245
Author(s):  
Constantin Oprea ◽  
Marilena Mierla ◽  
Georgeta Maris

AbstractIn this study we analyse the coronal mass ejections (CMEs) directed towards the Earth during the interval 2007–2010, using the data acquired by STEREO mission and those provided by SOHO, ACE and geomagnetic stations. A study of CMEs kinematics is performed. This is correlated with CMEs interplanetary manifestations and their geomagnetic effects, along with the energy transfer flux into magnetosphere (the Akasofu coupling function). The chosen interval that is practically coincident with the last solar minimum, offered us a good opportunity to link and analyse the chain of phenomena from the Sun to the terrestrial magnetosphere in an attempt to better understand the solar and heliospheric processes that can cause major geomagnetic storms.


2020 ◽  
Vol 10 ◽  
pp. 58
Author(s):  
Luca Giovannelli ◽  
Francesco Berrilli ◽  
Daniele Calchetti ◽  
Dario Del Moro ◽  
Giorgio Viavattene ◽  
...  

By the continuous multi-line observation of the solar atmosphere, it is possible to infer the magnetic and dynamical status of the Sun. This activity is essential to identify the possible precursors of space weather events, such as flare or coronal mass ejections. We describe the design and assembly of TSST (Tor Vergata Synoptic Solar Telescope), a robotic synoptic telescope currently composed of two main full-disk instruments, a Hα telescope and a Potassium (KI D1) magneto-optical filter (MOF)-based telescope operating at 769.9 nm. TSST is designed to be later upgraded with a second MOF channel. This paper describes the TSST concepts and presents the first light observation carried out in February 2020. We show that TSST is a low-cost robotic facility able to achieve the necessary data for the study of precursors of space weather events (using the magnetic and velocity maps by the MOF telescope) and fast flare detection (by the Hα telescope) to support Space Weather investigation and services.


2013 ◽  
Vol 8 (S300) ◽  
pp. 500-501
Author(s):  
Larisa Trichtchenko

AbstractCoronal mass ejections (CME) and associated interplanetary-propagated solar wind disturbances are the established causes of the geomagnetic storms which, in turn, create the most hazardous impacts on power grids. These impacts are due to the large geomagnetically induced currents (GIC) associated with variations of geomagnetic field during storms, which, flowing through the transformer windings, cause extra magnetisation. That can lead to transformer saturation and, in extreme cases, can result in power blackouts. Thus, it is of practical importance to study the solar causes of the large space weather events. This paper presents the example of the space weather chain for the event of 5-6 November 2001 and a table providing complete overview of the largest solar events during solar cycle 23 with their subsequent effects on interplanetary medium and on the ground. This compact overview can be used as guidance for investigations of the solar causes and their predictions, which has a practical importance in everyday life.


2004 ◽  
Vol 22 (10) ◽  
pp. 3741-3749 ◽  
Author(s):  
A. Gonzalez-Esparza ◽  
A. Santillán ◽  
J. Ferrer

Abstract. We studied the heliospheric evolution in one and two dimensions of the interaction between two ejecta-like disturbances beyond the critical point: a faster ejecta 2 overtaking a previously launched slower ejecta 1. The study is based on a hydrodynamic model using the ZEUS-3-D code. This model can be applied to those cases where the interaction occurs far away from the Sun and there is no merging (magnetic reconnection) between the two ejecta. The simulation shows that when the faster ejecta 2 overtakes ejecta 1 there is an interchange of momentum between the two ejecta, where the leading ejecta 1 accelerates and the tracking ejecta 2 decelerates. Both ejecta tend to arrive at 1AU having similar speeds, but with the front of ejecta 1 propagating faster than the front of ejecta 2. The momentum is transferred from ejecta 2 to ejecta 1 when the shock initially driven by ejecta 2 passes through ejecta 1. Eventually the two shock waves driven by the two ejecta merge together into a single stronger shock. The 2-D simulation shows that the evolution of the interaction can be very complex and there are very different signatures of the same event at different viewing angles; however, the transferring of momentum between the two ejecta follows the same physical mechanism described above. These results are in qualitative agreement with in-situ plasma observations of "multiple magnetic clouds" detected at 1AU.


This lecture is an attempt to review current knowledge about certain terrestrial phenomena with the twofold purpose: ( a ) to discover the extent to which the behaviour of the Earth may be influenced by fluctuations in its astronomical environment, ( b ) to see if new knowledge of that environment may be gained from its influence on the Earth. Fluctuations in geomagnetism, climate, glaciation, biological extinctions, etc., are surveyed with special regard to datings and characteristic time-intervals; correlations between such fluctuations are discussed. Astronomical phenomena, within the Solar System and elsewhere in the Galaxy, that might cause terrestrial effects are reviewed. As regards astronomical effects on Earth: (i) There is a good case - not yet overwhelming - for the currently widely accepted view that fluctuations of glaciation within an ice-epoch result from changes of insolation accompanying fluctuations of the Earth’s motion relative to the Sun. Some evidence suggests that an ice-epoch may be triggered by variations of the astronomical environment encountered in the Sun’s motion relative to the Galaxy; but tectonic changes on Earth may be the main trigger. (ii) Impacts of planetesimals may be more important than hitherto recognized. Among astronomical results regarding the Sun, while the intensity of solar ‘activity’ is variable, terrestrial effects provide no confirmation that the Sun is a ‘variable star’. Regarding the Galaxy, impacting planetesimals may originate in interstellar clouds, and so provide on Earth samples of interstellar matter. Some unsolved problems emphasized by the review are listed; certain concepts that would call for consideration in any extended review are mentioned.


2013 ◽  
Vol 8 (S300) ◽  
pp. 297-306 ◽  
Author(s):  
Robert F. Wimmer-Schweingruber

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.


2012 ◽  
Vol 8 (S294) ◽  
pp. 487-488
Author(s):  
Li-Jia Liu ◽  
Bo Peng

AbstractThe Sun affects the Earth in multiple ways. In particular, the material in interplanetary space comes from coronal expansion in the form of solar wind, which is the primary source of the interplanetary medium. Ground-based Interplanetary Scintillation (IPS) observations are an important and effective method for measuring solar wind speed and the structures of small diameter radio sources. In this paper we will discuss the IPS observations in China.


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