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Introduction to Magnetics
Published in Chen Wu, Jiaying Jin, Frontiers in Magnetic Materials, 2023
Magnetism is delicate as it cannot be seen or touched. It is, however, ubiquitous since the planet we live is a huge magnet due to the slow cooling of the liquid iron at the core of the earth (Davies et al., 2015). Despite of the small geomagnetic field (around 1/100 of that generated by a fridge magnet), it is critical to life on earth. Firstly, the geomagnetism protects us from cosmic radiation since it forms a magnetosphere consisting of charged particles, which deflects the solar wind from the earth. Secondly, geomagnetism has long been used for guidance of direction. Migrants such as turtles, whales and birds travel thousands of kilometers every year without getting lost thanks to their bio-sensitivity to the direction and strength of the geomagnetic field. Back in the period 206 BC–AD 220, the south pointer was invented based on the lodestone (Fe3O4) (Coey, 2010). This was later modified by Kuo Shen into the navigational compass in the 1100s, which later assisted in the discovery of Africa by He Zheng, and other great discoveries of new lands by Christopher Columbus, Vasco da Gama and Ferdinand Magellan after the 1400s. Thirdly, the geomagnetic field also aids mining for iron, nickel, chromium, etc., which also generate fields to alter the distribution of the geomagnetic field. If “magnetic minerals” are deformed under stress, their magnetism may change, based on which forecast of major earthquakes become possible.
Green Microwave and Satellite Communication Systems
Published in Gurjit Kaur, Akanksha Srivastava, Green Communication Technologies for Future Networks, 2023
Divya Sisodiya, Yash Bahuguna, Akanksha Srivastava, Gurjit Kaur
The satellites in LEO are shielded by the magnetosphere from the Sun’s charged particles and most of the cosmic rays from outer space. However, vehicles operating in GEO or interplanetary missions will be fully affected by these radiations (Yuan et al., 2016). As we all know, cosmic rays penetrate the integrated circuits of spacecraft autopilots and change data and commands. During solar storms, the space version of static electricity can accumulate in other spacecraft, generating electric sparks, which can cause serious problems with onboard electronic equipment. The empirical design of such systems reduces the impact of these effects (Ippolito et al., 2008).
Solar Activity as a Danger to Ground-based Technological Systems
Published in Olga Sokolova, Nikolay Korovkin, Masashi Hayakawa, Geomagnetic Disturbances Impacts on Power Systems, 2021
Olga Sokolova, Nikolay Korovkin, Masashi Hayakawa
One of the magnetosphere responses types is called substorm, which is caused by both dayside and nightside reconnection. It has both magnetospheric and auroral manifestations. The basic nature of substorm can be understood in terms of the overall Dungey model, modified by the expanding/contracting polar cap model, and the near Earth neutral line model [28]. Substorm is a cycle of energy storage and release consisting of three phases: growth (lasts up to 1 hour), expansion (20 minutes), and recovery (2–3 hours) [29]. When solar wind contains magnetic and plasma structures that impact magnetosphere over hours, such a response is called storm (geomagnetic disturbance).
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
The influenced ionosphere layers can cause major changes, such as changing the density distribution in the ionosphere, increasing or decreasing the TEC values, and impairing the current balance in the ionosphere (Komjathy, 1997). It is necessary to define the solar and geomagnetic activity indices and determine the solar and geomagnetic effect levels to model the changes in the ionosphere. We have used the following space weather condition indices: 1) solar activity indices (solar proxies): solar radio flux index (F10.7) and sunspot number (SSN); 2) geomagnetic storm index (Dst) and geomagnetic activity indices (Kp). The frequency of solar parameters and charged particle events from the Sun increases during solar maximum and causes significant variations in Earth’s magnetosphere and ionosphere. We have chosen the years 2014 to 2016 for this study due to 1) 2014 and 2015 being the years of the highest phase of the solar activity cycle-24, and 2016 being the year of the start of the solar decline; and 2) several geomagnetic events occurring during the interval. A typical mid-term response of the neutral atmosphere and ionosphere to the changes in solar and geomagnetic activity is known as ”quasi-27-day periodicity,” and the primary cause of such changes is the repeatable influence of active regions on the Sun’s surface that rotate with a period of 27 days (connected with solar rotation; Kutiev et al., 2013).
Towards the digital modelling of natural entities and its Pseudo-representation
Published in International Journal of Image and Data Fusion, 2022
Cifeng Wang, Ziming Zou, Xiaoyan Hu, Yunlong Li, Xi Bai
For the studies on the distribution of particles in the magnetosphere, the element entity mainly includes the magnetic field intensity and the particle flux. If we consider a bunch of specific particles, the element entity also includes the pitch angles and the velocity of these particles. Therefore, consider , such that: . Here, represents the magnetic field intensity, and . Furthermore, represents the particle flux of a certain type of particles, denoted by . The formalisation for and is field-based, with every cell of the spatial-temporal domain mapping to the element’s value space. On the other hand, represents the pitch angles of this bunch of particles under research, while is the velocity. Therefore, and . The mapping relations between these two elements and the spatial-temporal domain are built by mapping from a subset of the spatial-temporal domain, which is related to the bunch of particles’ current states, to the corresponding value space.
Study of space plasma waves with flow
Published in Radiation Effects and Defects in Solids, 2022
T. Smith, K. Strong, S. Ibenki, S. Sen
Similarly, large plasma fluid flows are also a hallmark of the Earth’s magnetosphere, magnetotail and plasma sheet. It has been recognized in early substorm research that high-speed plasma flows occur during substorms. In the plasmasphere, steep shear in ion flow velocity can exist due to the dominating co-rotating electric field inside the plasmasphere and a convective magnetospheric electric field penetrating across the plasmapause (4). Also, there are a number of observational confirmations of the presence of a variety of plasma flows in the upper levels of the solar atmosphere (spicules and macrospicules, reconnection outflows, jets in coronal holes, etc). Often, the plasma flows are directed along the magnetic field and are compact in the transversal direction. Note that the inhomogeneous flows do not always coincide with the inhomogeneities in the plasma density and magnetic field. Moreover, even in a homogeneous plasma there can be inhomogeneous flows, corresponding to the shifting of one plasma layer relative to another, along the magnetic field (5). Also, the boundaries between the fast and slow streams of the solar wind flow is also sheared.