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Mitigation of Negative Geomagnetic Disturbance Impacts on Power Systems
Published in Olga Sokolova, Nikolay Korovkin, Masashi Hayakawa, Geomagnetic Disturbances Impacts on Power Systems, 2021
Olga Sokolova, Nikolay Korovkin, Masashi Hayakawa
Many industrial sectors affected by space weather would like to receive the forecast on Bz amplitude within the 24 hours before the event. Moderate and severe events are also of interest to the customers, not only extreme. After the initial eruption, forecasters can map the event to Earth-arrival using a procedure shown in Fig. 5.4. Achieving this is associated with the set of difficulties. The main one is the orientation of the magnetic vectors within CMEs. A south directed solar wind magnetic field is more likely to heat the Earth's magnetosphere, causing the field lines to break and reconnect while releasing energy and causing geomagnetic storms [52]. Magnetic reconnection allows energy to enter the magnetosphere on the day-side, consequently, energy is stored and explosively released on the nightside. A model capable of predicting magnetic vectors with a lead time of more than 24 h is described in [75]. The other difficulty is that aforementioned SOHO and STEREO satellites are scientific missions, therefore scientific measurements and investigations have the higher priority. SWPC specialists control on GOES and DISCOVR satellites.
Orbital Radiation Environments
Published in John D. Cressler, H. Alan Mantooth, Extreme Environment Electronics, 2017
If only the trapped particle populations are considered, the inner zone is often dominated by radiation effects due to trapped protons while the outer zone is often dominated by radiation effects due to trapped electrons. Thus, recent trapped electron models have focused on the outer zone. A feature of the outer zone is its high degree of variability and dynamic behavior. This results from geomagnetic storms and substorms, which cause major perturbations of the geomagnetic field. Measurements from the Upper Atmosphere Research Satellite (UARS) illustrate the high degree of volatility of electron flux levels prior to and after such storms. For example, the difference in the 1 day averaged differential fluxes over a 9 day period is about three orders of magnitude for 1 MeV electrons [56]. Due to this volatile nature of the outer zone, probabilistic models have been developed [56,57] as well as worst-case models [58,59].
Magnetic Inrush Current in Distributed Photovoltaic Grid Power Transformers
Published in Hemchandra Madhusudan Shertukde, Distributed Photovoltaic Grid Transformers, 2017
Hemchandra Madhusudan Shertukde
During a solar storm, as the coronal mass ejection (CME) plasma cloud collides with the planet, large, transient, magnetic perturbations overlay and alter the normally stable magnetic field of Earth. These magnetic perturbations are referred to as a geomagnetic storm and can affect the planet for a period of a day or two. These perturbations can induce voltage variations along the surface of the planet and induce electric fields in the Earth to create potential differences in voltage between grounding points, which causes geomagnetic-induced currents (GICs) to flow through transformers, power system lines, and grounding points. GICs can severely affect grounded wye-connected transformers and autotransformers through its Earth-neutral connection.
Medium-term ionospheric response to the solar and geomagnetic conditions at low-latitude stations of the East African sector
Published in Cogent Engineering, 2023
Shumet Woldemariam, Tsegaye Gogie
Geomagnetic storms happen when the solar wind speed increases significantly and abruptly, as explained in Schunk and Sojka (1996). When the enhanced solar wind speed is accompanied by a significant southerly IMF component, storms can be especially potent. Large storms have the potential to drastically alter the ionosphere-thermosphere system’s density, composition, and circulation on a global scale, and these changes may last for several days after the geomagnetic activity has subsided. As a result of storm dynamics, an increase in electron density is referred to as a ”positive ionospheric storm,” and a drop in electron density is referred to as a ”negative ionospheric storm.” The following factors are involved in the mechanisms that account for the positive ionospheric storm: First, a rise in oxygen density; second, the meridional winds change, causing the ionosphere to ascend to higher altitudes where the recombination rates are lower; third, an eastward electric field that uplifts the ionosphere and directs it to areas with lower recombination rates; and fourth, plasma redistribution as a result of disturbed electric fields. A reduction in the density ratio as a result of atmospheric disturbances, on the other hand, is what triggers the negative storm phase, which is brought on by changes in neutral composition (De Abreu et al., 2014, 2010; Blanch et al., 2013; Fagundes et al., 2016; Goncharenko et al., 2007; Huang et al., 2005).
DWT-based methodology for detection of seismic precursors on electric field signals in Mexico
Published in Geomatics, Natural Hazards and Risk, 2018
O. Chavez, J. R. Millan-Almaraz, J. Rodríguez-Reséndiz, J. P. Amezquita-Sanchez, M. Valtierra-Rodriguez, J. A. L. Cruz-Abeyro
It has been reported that the atmospheric electrical phenomena generate EM signals in ULF and very-low frequency (VLF) bands (Hayakawa and Hobara 2010; Athanasiou et al. 2011). In this regard, geomagnetic storms may disturb large territories in the planet due to atmospheric electrical currents that are related to the geo-magnetic field. These pre-seismic phenomena can be observed depending on their type, magnitude, and seismic event depth (Arikan et al. 2012), which generate a limit to distinguish pre-seismic data from EM storm noise (Devi et al. 2014). Other reports show that there exist a relation between a seismic event and the atmospheric electrical current disturbances based on electron density (Ne) and electron temperature (Te) methods. These techniques were implemented on DEMETER satellite located at 630 km altitude (Athanasiou et al. 2011; Liu et al. 2014).
An Observational Review on influence of Intense Geomagnetic Storm on Positional Accuracy of NavIC/IRNSS System
Published in IETE Technical Review, 2020
Mehul V. Desai, Shweta N. Shah
NavIC/IRNSS signals propagating through the low latitude ionosphere are very susceptible to the inhomogeneous, anisotropic, and dispersive nature of the ionosphere which can introduce additional delay in the signals followed by degradation of the positional accuracy of the system [8–11]. These degradations depend on the Total Electron Content (TEC), signal frequency and on the elevation angle of NavIC/IRNSS satellites above the horizon [4]. The variation in TEC depends on geographical locations and solar/geophysical events, such as solar flares and geomagnetic storms [12]. Geomagnetic storm occurs when the Earth's magnetic field is affected by an Interplanetary Coronal Mass Ejection (ICME) or high-speed stream.