scholarly journals Solar Rotation Multiples in Space-Weather Effects

Solar Physics ◽  
2021 ◽  
Vol 296 (8) ◽  
Author(s):  
Agnieszka Gil ◽  
Renata Modzelewska ◽  
Anna Wawrzaszek ◽  
Bozena Piekart ◽  
Tadeusz Milosz

AbstractThe solar rotation period is the most prominent mid-term periodicity in the temporal behaviour of solar, heliospheric, and geomagnetic parameters. It is also a cause of the repeatedly appearing geomagnetic storms originating from the corotating interaction regions (CIRs). Since geomagnetic CIR-driven storms have a natural periodic character, and geomagnetic storms impact energy infrastructure via geomagnetically induced currents, it is of interest whether this periodic character is also noticeable in the temporal behaviour of electrical-grid failures (EGFs), which, at least to some extent, might be of solar origin.

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.


Space Weather ◽  
2016 ◽  
Vol 14 (12) ◽  
pp. 1136-1154 ◽  
Author(s):  
Seán P. Blake ◽  
Peter T. Gallagher ◽  
Joe McCauley ◽  
Alan G. Jones ◽  
Colin Hogg ◽  
...  

2020 ◽  
Author(s):  
Joana Alves Ribeiro ◽  
Maria Alexandra Pais ◽  
Fernando J. G. Pinheiro ◽  
Fernando A. Monteiro Santos ◽  
Pedro Soares

<p>The MAG-GIC project has as a main goal to produce the chart of Geomagnetically Induced Currents (GIC) risk hazard in the distribution power network of Portugal mainland.</p><p>The study of GICs is important as they represent a threat for infrastructures such as power grids, pipelines, telecommunication cables, and railway systems. A deeper insight into GICs hazard may help in planning and designing more resilient transmission systems and help with criteria for equipment selection.</p><p>GICs are a result of variations in the ionospheric and magnetospheric electric currents, that cause changes in the Earth's magnetic field. The Coimbra magnetic observatory (COI) is one of the oldest observatories in operation in the world and the only one in Portugal mainland. It has been (almost) continuously monitoring the geomagnetic field variations since 1866, and in particular, it has registered the imprint of geomagnetic storms during solar cycle 24. Besides the geomagnetic storm signal, which represents the GICs driver, the crust and upper mantle electrical conductivities determine the amplitude and geometry of the induced electric fields.</p><p>To present a better approximation of the Earth's conductivity structure below the Portuguese power network, we initiated a campaign to acquire magnetotelluric (MT) data in a grid of 50x50 km all over the territory. Nonetheless, there already exist enough MT data to create a realistic 3D conductivity model in the south of Portugal.</p><p>The other important input is the electric circuit for the network grid. We benefit from the collaboration of the Portuguese high voltage power network (REN) company, in providing the grid parameters as resistances and transformer locations, thus allowing us to construct a more precise model. In particular, we implement in our model the effect of shield wires and shunt reactors resistances.</p><p>In this study, we present the results of GIC calculations for the south of Portugal for some of the strongest geomagnetic storms in the 20015-17 period recorded at COI during solar cycle 24. We will focus on the sensitivity of results concerning two different conductivity models and different values of the shielding circuit parameters and shunt reactors devices.</p>


2020 ◽  
Author(s):  
Timofey Sagitov ◽  
Roman Kislov

<p>High speed streams originating from coronal holes are long-lived plasma structures that form corotating interaction regions (CIRs) or stream interface regions (SIRs) in the solar wind. The term CIR is used for streams existing for at least one solar rotation period, and the SIR stands for streams with a shorter lifetime. Since the plasma flows from coronal holes quasi-continuously, CIRs/SIRs simultaneously expand and rotate around the Sun, approximately following the Parker spiral shape up to the Earth’s orbit.</p><p>Coronal hole streams rotate not only around the Sun but also around their own axis of simmetry, resembling a screw. This effect may occur because of the following mechanisms: (1) the existence of a difference between the solar wind speed at different sides of the stream, (2) twisting of the magnetic field frozen into the plasma, and  (3) a vortex-like motion of the edge of the mothering coronal hole at the Sun. The screw type of the rotation of a CIR/SIR can lead to centrifugal instability if CIR/SIR inner layers have a larger angular velocity than the outer. Furthermore, the rotational plasma movement and the stream distortion can twist magnetic field lines. The latter contributes to the pinch effect in accordance with a well-known criterion of Suydam instability (Newcomb, 1960, doi: 10.1016/0003-4916(60)90023-3). Owing to the presence of a cylindrical current sheet at the boundary of a coronal hole, conditions for tearing instability can also appear at the CIR/SIR boundary. Regardless of their geometry, large scale current sheets are subject to various instabilities generating plasmoids. Altogether, these effects can lead to the formation of a turbulent region within CIRs/SIRs, making them filled with current sheets and plasmoids. </p><p>We study a substructure of CIRs/SIRs, characteristics of their rotation in the solar wind, and give qualitative estimations of possible mechanisms which lead to splitting of the leading edge a coronal hole flow and consequent formation of current sheets within CIRs/SIRs.</p>


2019 ◽  
Vol 115 (1/2) ◽  
Author(s):  
Emmanuel Nahayo ◽  
Pieter B. Kotzé ◽  
Pierre J. Cilliers ◽  
Stefan Lotz

Geomagnetic storms are space weather events that result in a temporary disturbance of the earth’s magnetosphere caused by a solar wind that interacts with the earth’s magnetic field. We examined more closely how some southern African magnetic observatories responded to the Saint Patrick’s Day storm using local K-indices. We show how this network of observatories may be utilised to model induced electric field, which is useful for the monitoring of geomagnetically induced anomalous currents capable of damaging power distribution infrastructure. We show an example of the correlation between a modelled induced electric field and measured geomagnetically induced currents in southern Africa. The data show that there are differences between global and local indices, which vary with the phases of the storm. We show the latitude dependence of geomagnetic activity and demonstrate that the direction of the variation is different for the X and Y components. Significance: • The importance of ground-based data in space weather studies is demonstrated. • We show how SANSA’s geomagnetic network may be utilised to model induced electric field, which is useful for the monitoring of geomagnetically induced anomalous currents capable of damaging power distribution infrastructure.


2017 ◽  
Vol 35 (3) ◽  
pp. 751-761 ◽  
Author(s):  
Rachel L. Bailey ◽  
Thomas S. Halbedl ◽  
Ingrid Schattauer ◽  
Alexander Römer ◽  
Georg Achleitner ◽  
...  

Abstract. Geomagnetically induced currents (GICs) in power systems, which can lead to transformer damage over the short and the long term, are a result of space weather events and geomagnetic variations. For a long time, only high-latitude areas were considered to be at risk from these currents, but recent studies show that considerable GICs also appear in midlatitude and equatorial countries. In this paper, we present initial results from a GIC model using a thin-sheet approach with detailed surface and subsurface conductivity models to compute the induced geoelectric field. The results are compared to measurements of direct currents in a transformer neutral and show very good agreement for short-period variations such as geomagnetic storms. Long-period signals such as quiet-day diurnal variations are not represented accurately, and we examine the cause of this misfit. The modelling of GICs from regionally varying geoelectric fields is discussed and shown to be an important factor contributing to overall model accuracy. We demonstrate that the Austrian power grid is susceptible to large GICs in the range of tens of amperes, particularly from strong geomagnetic variations in the east–west direction.


2011 ◽  
Vol 413 ◽  
pp. 129-132
Author(s):  
You Jie Ma ◽  
Dong Fang Wu ◽  
Xue Song Zhou

The geomagnetic storm which is caused by the sun's activity is a global natural disaster. When the sun surface activity is exuberant, especially in sun spots period, the surface of the sun will release X-ray, ultraviolet, visible and high-energy proton or electron beam. Part of the charged particles form current and influence the earth's magnetic field, current shock caused severe change occurs, geomagnetic happens. it can induce Geomagnetically induced currents (GIC).The GIC has very big effect on various man-made long distance conductors. The electric field produced during a geomagnetic disturbance is dependent on the magnitude and frequency of magnetic field variations and the Earth’s surface impedance. The GIC in a conductor system is also related to the infrastructure of the system. This paper introduces the principle of GIC, algorithm method and the geomagnetic storms rules.


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