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Geomagnetic Field Effects on Living Systems
Published in Shoogo Ueno, Tsukasa Shigemitsu, Bioelectromagnetism, 2022
The GMF intensity was about half of the current one 4.2 billion years ago (Ga = giga-annum = 109 years), but it became about the current intensity 4.1–4.0 Ga, and again about half the current one 3.9–3.3 Ga, and since about 2.7–2.1 Ga, it remains as large as the present intensity (Tarduno et al., 2007, 2010). The magnetosphere is the region above the ionosphere that is defined by the extent of the GMF in space. It extends several tens of thousands of kilometers into space, protecting the Earth from the charged particles of the solar wind and GCRs that would otherwise strip away the upper atmosphere, including the ozone layer that protects the Earth from the potentially harmful UV-B (280–315 nm) radiation. The ionosphere is the ionized part of Earth’s upper atmosphere, from about 48 to 965 km altitude (Zell, 2020). The ionosphere is ionized by solar radiation. It plays an important role in atmospheric electricity and forms the inner edge of the magnetosphere. It has practical importance because, among other functions, it influences radio propagation to distant places on the Earth (Rawer, 1993). The coupling currents or field-aligned currents flow along magnetic field (MF) lines between the magnetosphere and ionosphere. One of the manifestations of the coupling currents is the auroral oval (e.g., Nagata and Kokubun, 1962).
Petroleum Geo-Electrical Survey
Published in Muhammad Abdul Quddus, Petroleum Science and Technology, 2021
The origin of the telluric current and magnetic field is the ionosphere. The ionosphere is the upper portion of the earth’s atmosphere (90–500 km above sea level) containing charged (ionized) particles. The charged particles generate a magnetic field. The magnetic field starting from the ionosphere and reaching earth is known as the telluric magnetic field. The radiation from the sun and the earth’s rotation leads to variation in the telluric magnetic field. The variation of earth’s magnetic field also introduces telluric current in the earth. The variation of the telluric magnetic field induces an AC current of low frequency in the earth.
Atmosphere
Published in Wayne T. Davis, Joshua S. Fu, Thad Godish, Air Quality, 2021
Wayne T. Davis, Joshua S. Fu, Thad Godish
This ionized layer of the thermosphere is described as the ionosphere. It is responsible for the formation of the aurora borealis (northern lights) and aurora australis (southern lights). Auroras are closely related in time with solar flare activity and occur at the Earth’s magnetic poles. As masses of protons and electrons approach the Earth from the sun, they are captured by its magnetic field, which moves them toward the poles. As these ions move, O2 and N2 are energized, emitting light characteristic of auroral displays.
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 Sun is a highly variable star with sporadic events consisting of outbursts and huge amounts of energy. Our planet obtains energy from the Sun through electromagnetic radiation, solar wind, and the IMF (Interplanetary Magnetic Field). The Earth’s atmosphere can be classified into several different layers based on the activity of the Sun, the gravity and magnetic field of the Earth, the temperature, and the degree of ionization. A neutral atmosphere can extend up to 60 km, and the ionosphere can extend from about 60 km to more than 1,000 km altitude (Appleton & Barnett, 1925; Breit & Tuve, 1925; Chapman, 1931; Heaviside, 1902; Kennelly, 1902; Ratcliffe, 1972; Taylor, 1903). There are numerous ways that active solar areas affect the magnetosphere and ionosphere of Earth. The various driving mechanisms collectively contribute to the variation of neutral and ionized densities (Kutiev et al., 2013). The ionospheric response is latitude-dependent and causes large horizontal gradients. These gradients are evaluated using Global Navigation Satellite Systems (GNSS) measurements of the total electron content (TEC). The ionosphere activity can be monitored by considering TEC observations derived from a network of GPS stations using dual-frequency measurements (Wanninger, 1993).
Characterizing the accuracy of Global Positioning System for single point positioning at African low-latitude region
Published in Journal of Spatial Science, 2023
Oladipo Emmanuel Abe, Babatunde Adeyemi, Olugbenga Ogunmodimu, Israel Emmanuel, E.J. Oluwadare, T.S. Oluwadare
Walter et al. (2001) reported that when the ionosphere over North America is disturbed due to geomagnetic storms, the American satellite augmentation system known as the Wide Area Augmentation System (WAAS) significantly falls short of its confidence bound. Tiwari et al. (2009) examined the efficiency of the GPS within the equatorial region of Africa as well as the effect of the ionosphere on satellite geometry; they also observed that when the ionosphere changes from its undisturbed state to more turbulent states, GPS applications are affected. Accuracy and reliability of GPS signals suffer from the variation of the ionosphere. The ionosphere over equatorial regions has more effect on radio wave propagation (SIWG 2012), because it extends to ±20° of geomagnetic latitudes. This is the most active region on the globe and it is more dynamic and complex due to many phenomena that occur in low-latitude regions. In the equatorial region, the spatial and temporal variability is much greater than in middle latitude regions even during geomagnetically quiet conditions (Hargreaves 1992).
Study of space plasma waves with flow
Published in Radiation Effects and Defects in Solids, 2022
T. Smith, K. Strong, S. Ibenki, S. Sen
As mentioned above, the ionosphere plays a major role in space weather due to its important influence on the propagation of electromagnetic waves. A variety of physical phenomena associated with space weather, including geomagnetic storms and substorms, energization of the Van Allen radiations belts, ionospheric disturbances and scintillation and geomagnetically induced currents at Earth’s surface, are directly or indirectly related to various waves, instabilities and turbulences generated in the space plasma environment of the upper atmosphere. So, the proposed research will benefit all ‘technological systems’ that encounter space weather induced problems, such as, the electrical networks for power transmission, space-borne synthetic aperture radars, global positioning and navigation systems using satellites, geomagnetic surveys, and pipelines (corrosion effects), etc.