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The magnetopause is the abrupt boundary between a magnetosphere and the surrounding plasma. For planetary science, the magnetopause is the boundary between the planet's magnetic field and the solar wind. The location of the magnetopause is determined by the balance between the pressure of the dynamic planetary magnetic field and the dynamic pressure of the solar wind. As the solar wind pressure increases and decreases, the magnetopause moves inward and outward in response. Waves along the magnetopause move in the direction of the solar wind flow in response to small-scale variations in the solar wind pressure and to Kelvin–Helmholtz instability.
The solar wind is a stream of charged particles released from the upper atmosphere of the Sun, called the corona. This plasma mostly consists of electrons, protons and alpha particles with kinetic energy between 0.5 and 10 keV. The composition of the solar wind plasma also includes a mixture of materials found in the solar plasma: trace amounts of heavy ions and atomic nuclei of elements such as C, N, O, Ne, Mg, Si, S, and Fe. There are also rarer traces of some other nuclei and isotopes such as P, Ti, Cr, and 58Ni, 60Ni, and 62Ni. Superimposed with the solar-wind plasma is the interplanetary magnetic field. The solar wind varies in density, temperature and speed over time and over solar latitude and longitude. Its particles can escape the Sun's gravity because of their high energy resulting from the high temperature of the corona, which in turn is a result of the coronal magnetic field. The boundary separating the corona from the solar wind is called the Alfvén surface.
An aurora , also commonly known as the northern lights or southern lights, is a natural light display in Earth's sky, predominantly seen in high-latitude regions. Auroras display dynamic patterns of brilliant lights that appear as curtains, rays, spirals, or dynamic flickers covering the entire sky.
Cluster II is a space mission of the European Space Agency, with NASA participation, to study the Earth's magnetosphere over the course of nearly two solar cycles. The mission is composed of four identical spacecraft flying in a tetrahedral formation. As a replacement for the original Cluster spacecraft which were lost in a launch failure in 1996, the four Cluster II spacecraft were successfully launched in pairs in July and August 2000 onboard two Soyuz-Fregat rockets from Baikonur, Kazakhstan. In February 2011, Cluster II celebrated 10 years of successful scientific operations in space. In February 2021, Cluster II celebrated 20 years of successful scientific operations in space. As of March 2023, its mission has been extended until September 2024. The China National Space Administration/ESA Double Star mission operated alongside Cluster II from 2004 to 2007.
A Birkeland current is a set of electrical currents that flow along geomagnetic field lines connecting the Earth's magnetosphere to the Earth's high latitude ionosphere. In the Earth's magnetosphere, the currents are driven by the solar wind and interplanetary magnetic field and by bulk motions of plasma through the magnetosphere. The strength of the Birkeland currents changes with activity in the magnetosphere. Small scale variations in the upward current sheets accelerate magnetospheric electrons which, when they reach the upper atmosphere, create the Auroras Borealis and Australis. In the high latitude ionosphere, the Birkeland currents close through the region of the auroral electrojet, which flows perpendicular to the local magnetic field in the ionosphere. The Birkeland currents occur in two pairs of field-aligned current sheets. One pair extends from noon through the dusk sector to the midnight sector. The other pair extends from noon through the dawn sector to the midnight sector. The sheet on the high latitude side of the auroral zone is referred to as the Region 1 current sheet and the sheet on the low latitude side is referred to as the Region 2 current sheet.
A double layer is a structure in a plasma consisting of two parallel layers of opposite electrical charge. The sheets of charge, which are not necessarily planar, produce localised excursions of electric potential, resulting in a relatively strong electric field between the layers and weaker but more extensive compensating fields outside, which restore the global potential. Ions and electrons within the double layer are accelerated, decelerated, or deflected by the electric field, depending on their direction of motion.
Electromagnetic hiss is a naturally occurring Extremely Low Frequency/Very Low Frequency electromagnetic wave that is generated in the plasma of either the Earth's ionosphere or magnetosphere. Its name is derived from its incoherent, structureless spectral properties which, when played through an audio system, sound like white noise.
The impact of the solar wind onto the magnetosphere generates an electric field within the inner magnetosphere - the convection field-. Its general direction is from dawn to dusk. The co-rotating thermal plasma within the inner magnetosphere drifts orthogonal to that field and to the geomagnetic field Bo. The generation process is not yet completely understood. One possibility is viscous interaction between solar wind and the boundary layer of the magnetosphere (magnetopause). Another process may be magnetic reconnection. Finally, a hydromagnetic dynamo process in the polar regions of the inner magnetosphere may be possible. Direct measurements via satellites have given a fairly good picture of the structure of that field. A number of models of that field exists.
STEVE is an atmospheric optical phenomenon that appears as a purple and green light ribbon in the sky, named in late 2016 by aurora watchers from Alberta, Canada. According to analysis of satellite data from the European Space Agency's Swarm mission, the phenomenon is caused by a 25 km (16 mi) wide ribbon of hot plasma at an altitude of 450 km (280 mi), with a temperature of 3,000 °C and flowing at a speed of 6 km/s (3.7 mi/s). The phenomenon is not rare, but had not been investigated and described scientifically prior to that time.
Alexander J. Dessler was an American space scientist known for conceiving the term heliosphere and for founding the first Space Science Department in the United States.
Richard Mansergh Thorne was an American physicist and a distinguished professor in the department of atmospheric and oceanic sciences at UCLA. He was known for his contributions to space plasma physics. He was a fellow of the American Geophysical Union.
Mei-Ching Hannah Fok is a planetary scientist at the Goddard Space Flight Center. She was awarded the NASA Exceptional Scientific Achievement Medal in 2011 and elected a Fellow of the American Geophysical Union in 2019. She has worked on the IMAGE, Van Allen Probes and TWINS missions.
David Breed Beard was a space physicist, known for "pioneering work on the shapes and structures of planetary magnetospheres, Jovian radio emissions, and comets."
Wen Li is a space physicist at Boston University. Her research interests include space plasma waves, Earth's radiation belt physics, solar-wind magnetosphere coupling, energetic particle precipitation, and Jovian magnetosphere and aurora: She is a Fellow of the American Geophysical Union.
Meers Oppenheim is an American physicist who is Professor of Astronomy at Boston University. His primary research interests include computational and theoretical space plasma physics, dynamics of the ionosphere and solar atmosphere, particle-wave interactions in plasmas, and the physics of meteor trails.
Cynthia Cattell is a space plasma physicist known for her research on solar flares and radiation belts.
Antoinette (Toni) Galvin is space physicist at the University of New Hampshire. She is known for her research on the solar wind.
Michelle F. Thomsen is space physicist known for her research on the magnetospheres of Earth, Jupiter, and Saturn.
Vania Koleva Jordanova is a physicist known for her work on space weather and geomagnetic storms. She was elected a fellow of the American Geophysical Union in 2021.
James Wynne Dungey (1923–2015) was a British space scientist who was pivotal in establishing the field of space weather and made significant contributions to the fundamental understanding of plasma physics.
References
- 1 2 "Lynn Kistler". UNH Earth, Oceans, & Space. 18 July 2018.
- ↑ "Kistler". Honors Program.
- ↑ Kistler, L. M.; Ipavich, F. M.; Hamilton, D. C.; Gloeckler, G.; Wilken, B.; Kremser, G.; Stüdemann, W. (1989). "Energy spectra of the major ion species in the ring current during geomagnetic storms". Journal of Geophysical Research. 94 (A4): 3579. Bibcode:1989JGR....94.3579K. doi:10.1029/JA094iA04p03579.
- ↑ "ESA Science & Technology - Cluster makes crucial step in understanding space weather". sci.esa.int. Retrieved 2021-07-13.
- ↑ Kistler, L. M.; Mouikis, C. G.; Klecker, B.; Dandouras, I. (2010). "Cusp as a source for oxygen in the plasma sheet during geomagnetic storms: OXYGEN IN THE PLASMA SHEET-CUSP SOURCE". Journal of Geophysical Research: Space Physics. 115 (A3): n/a. Bibcode:2010JGRA..115.3209K. doi: 10.1029/2009JA014838 .
- ↑ NASA. "NASA Selects Science Investigations for Concept Studies". www.prnewswire.com (Press release). Retrieved 2021-07-13.
- ↑ "University of New Hampshire scientists land roles in European and Japanese space missions". EurekAlert!. Retrieved 2021-07-13.
- ↑ "Harvey Mudd College Magazine, summer 2017". Issuu. 2017. Retrieved 2021-07-13.
- ↑ Owen, C. J.; Bruno, R.; Livi, S.; Louarn, P.; Janabi, K. Al; Allegrini, F.; Amoros, C.; Baruah, R.; Barthe, A.; Berthomier, M.; Bordon, S. (2020-10-01). "The Solar Orbiter Solar Wind Analyser (SWA) suite" (PDF). Astronomy & Astrophysics. 642: A16. Bibcode:2020A&A...642A..16O. doi: 10.1051/0004-6361/201937259 . ISSN 0004-6361. S2CID 224966409.
- ↑ "Kistler". Honors Program.
- ↑ "Prof. Lynn Kistler is awarded the 2023 AGU Van Allen Lecture Award" . Retrieved 2024-01-12.
