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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.
Van Allen radiation belt is a zone of energetic charged particles, most of which originate from the solar wind, that are captured by and held around a planet by that planet's magnetosphere. Earth has two such belts, and sometimes others may be temporarily created. The belts are named after James Van Allen, who is often credited with their discovery.
A whistler is a very low frequency (VLF) electromagnetic (radio) wave generated by lightning. Frequencies of terrestrial whistlers are 1 kHz to 30 kHz, with maximum frequencies usually at 3 kHz to 5 kHz. Although they are electromagnetic waves, they occur at audio frequencies, and can be converted to audio using a suitable receiver. They are produced by lightning strikes where the impulse travels along the Earth's magnetic field lines from one hemisphere to the other. They undergo dispersion of several kHz due to the slower velocity of the lower frequencies through the plasma environments of the ionosphere and magnetosphere. Thus they are perceived as a descending tone which can last for a few seconds. The study of whistlers categorizes them into Pure Note, Diffuse, 2-Hop, and Echo Train types.
The magnetosphere of Saturn is the cavity created in the flow of the solar wind by the planet's internally generated magnetic field. Discovered in 1979 by the Pioneer 11 spacecraft, Saturn's magnetosphere is the second largest of any planet in the Solar System after Jupiter. The magnetopause, the boundary between Saturn's magnetosphere and the solar wind, is located at a distance of about 20 Saturn radii from the planet's center, while its magnetotail stretches hundreds of Saturn radii behind it.
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.
The Global Geospace Science (GGS) Wind satellite is a NASA science spacecraft designed to study radio waves and plasma that occur in the solar wind and in the Earth's magnetosphere. It was launched on 1 November 1994, at 09:31:00 UTC, from launch pad LC-17B at Cape Canaveral Air Force Station (CCAFS) in Merritt Island, Florida, aboard a McDonnell Douglas Delta II 7925-10 rocket. Wind was designed and manufactured by Martin Marietta Astro Space Division in East Windsor Township, New Jersey. The satellite is a spin-stabilized cylindrical satellite with a diameter of 2.4 m and a height of 1.8 m.
The plasmasphere, or inner magnetosphere, is a region of the Earth's magnetosphere consisting of low-energy (cool) plasma. It is located above the ionosphere. The outer boundary of the plasmasphere is known as the plasmapause, which is defined by an order of magnitude drop in plasma density. In 1963 American scientist Don Carpenter and Soviet astronomer Konstantin Gringauz proved the plasmasphere and plasmapause's existence from the analysis of very low frequency (VLF) whistler wave data. Traditionally, the plasmasphere has been regarded as a well behaved cold plasma with particle motion dominated entirely by the geomagnetic field and, hence, co-rotating with the Earth.
Time History of Events and Macroscale Interactions during Substorms (THEMIS) mission began in February 2007 as a constellation of five NASA satellites to study energy releases from Earth's magnetosphere known as substorms, magnetic phenomena that intensify auroras near Earth's poles. The name of the mission is an acronym alluding to the Titan Themis.
The magnetosphere of Jupiter is the cavity created in the solar wind by Jupiter's magnetic field. Extending up to seven million kilometers in the Sun's direction and almost to the orbit of Saturn in the opposite direction, Jupiter's magnetosphere is the largest and most powerful of any planetary magnetosphere in the Solar System, and by volume the largest known continuous structure in the Solar System after the heliosphere. Wider and flatter than the Earth's magnetosphere, Jupiter's is stronger by an order of magnitude, while its magnetic moment is roughly 18,000 times larger. The existence of Jupiter's magnetic field was first inferred from observations of radio emissions at the end of the 1950s and was directly observed by the Pioneer 10 spacecraft in 1973.
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.
Margaret Galland Kivelson is an American space physicist, planetary scientist, and distinguished professor emerita of space physics at the University of California, Los Angeles. From 2010 to the present, concurrent with her appointment at UCLA, Kivelson has been a research scientist and scholar at the University of Michigan. Her primary research interests include the magnetospheres of Earth, Jupiter, and Saturn.
Robyn Margaret Millan is an American experimental physicist, best known for her work on radiation belts that surround the Earth.
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.
Cynthia Cattell is a space plasma physicist known for her research on solar flares and radiation belts.
Mary Hudson is the Eleanor and Kelvin Smith Distinguished Professor of Physics at Dartmouth College. She is known for her research on the weather patterns that occur due to solar eruptions. She was elected a fellow of the American Geophysical Union in 1984.
Michelle F. Thomsen is space physicist known for her research on the magnetospheres of Earth, Jupiter, and Saturn.
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 "Meet BU's Six NSF CAREER Award Recipients". Boston University. Retrieved 2021-09-06.
- ↑ "Wen Li BU Profile". BU Center for Space Physics. Retrieved 1 March 2021.
- 1 2 3 "Home". home. Retrieved 2021-09-06.
- ↑ "NSF Award Search: Award # 1847818 - CAREER: Exploring Mysterious Whistler Mode Waves in Earth's Plasmaspheric Plumes". www.nsf.gov. Retrieved 2021-09-09.
- 1 2 3 Home, Richard. "Wen Li". AGU. Retrieved 28 July 2021.
- ↑ Thorne, R; Li, W; Ni, B (2013). "Rapid local acceleration of relativistic radiation-belt electrons by magnetospheric chorus". Nature. 504 (7480): 411–414. Bibcode:2013Natur.504..411T. doi:10.1038/nature12889. PMID 24352287. S2CID 4387148 . Retrieved 14 September 2021.
- ↑ Li, W; Shprits, R; Thorne, M (23 October 2007). "Dynamic evolution of energetic outer zone electrons due to wave-particle interactions during storms". Journal of Geophysical Research. 112 (A10). Bibcode:2007JGRA..11210220L. doi:10.1029/2007JA012368.
- ↑ Li, W; Thorne, R; Angelopoulos, V; Bortnik, J; Cully, C; Ni, B; LeContel, O; Roux, A; Auster, U; Magnes, W (May 2009). "Global distribution of whistler-mode chorus waves observed on the THEMIS spacecraft". Geophysical Research Letters. 36 (9). Bibcode:2009GeoRL..36.9104L. doi: 10.1029/2009GL037595 . S2CID 120391902.
- ↑ "AFOSR awards grants to 57 scientists and engineers through its Young Investigator Research Program". WRIGHT-PATTERSON AFB. 20 January 2015. Retrieved 28 July 2021.
- ↑ "Young Scientists". International Union of Radio Science. Retrieved 28 July 2021.
- ↑ "Boston University". Alfred P. Sloan Foundation. Retrieved 28 July 2021.
- ↑ "Award Abstract # 1847818 CAREER: Exploring Mysterious Whistler Mode Waves in Earth's Plasmaspheric Plumes". National Science Foundation. Retrieved 28 July 2021.
