Related Research Articles
A corona is the outermost layer of a star's atmosphere. It is a hot but relatively dim region of plasma populated by intermittent coronal structures known as solar prominences or filaments.
The Sun is the star at the center of the Solar System. It is a massive, nearly perfect sphere of hot plasma, heated to incandescence by nuclear fusion reactions in its core, radiating the energy from its surface mainly as visible light and infrared radiation with 10% at ultraviolet energies. It is by far the most important source of energy for life on Earth. The Sun has been an object of veneration in many cultures. It has been a central subject for astronomical research since antiquity.
The solar wind is a stream of charged particles released from the Sun's outermost atmospheric layer, 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 particle species found in the solar plasma: trace amounts of heavy ions and atomic nuclei of elements such as carbon, nitrogen, oxygen, neon, magnesium, silicon, sulfur, and iron. There are also rarer traces of some other nuclei and isotopes such as phosphorus, titanium, chromium, and nickel's isotopes 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.
In plasma physics, an Alfvén wave, named after Hannes Alfvén, is a type of plasma wave in which ions oscillate in response to a restoring force provided by an effective tension on the magnetic field lines.
The heliosphere is the magnetosphere, astrosphere, and outermost atmospheric layer of the Sun. It takes the shape of a vast, tailed bubble-like region of space. In plasma physics terms, it is the cavity formed by the Sun in the surrounding interstellar medium. The "bubble" of the heliosphere is continuously "inflated" by plasma originating from the Sun, known as the solar wind. Outside the heliosphere, this solar plasma gives way to the interstellar plasma permeating the Milky Way. As part of the interplanetary magnetic field, the heliosphere shields the Solar System from significant amounts of cosmic ionizing radiation; uncharged gamma rays are, however, not affected. Its name was likely coined by Alexander J. Dessler, who is credited with the first use of the word in the scientific literature in 1967. The scientific study of the heliosphere is heliophysics, which includes space weather and space climate.
The Solar Orbiter (SolO) is a Sun-observing probe developed by the European Space Agency (ESA) with a National Aeronautics and Space Administration (NASA) contribution. Solar Orbiter, designed to obtain detailed measurements of the inner heliosphere and the nascent solar wind, will also perform close observations of the polar regions of the Sun which is difficult to do from Earth. These observations are important in investigating how the Sun creates and controls its heliosphere.
Cluster II was 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 was 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 was extended until September 2024. The China National Space Administration/ESA Double Star mission operated alongside Cluster II from 2004 to 2007.
Solar physics is the branch of astrophysics that specializes in the study of the Sun. It intersects with many disciplines of pure physics and astrophysics.
Heliophysics is the physics of the Sun and its connection with the Solar System. NASA defines heliophysics as "(1) the comprehensive new term for the science of the Sun - Solar System Connection, (2) the exploration, discovery, and understanding of Earth's space environment, and (3) the system science that unites all of the linked phenomena in the region of the cosmos influenced by a star like our Sun."
Coronal seismology is a technique of studying the plasma of the Sun's corona with the use of magnetohydrodynamic (MHD) waves and oscillations. Magnetohydrodynamics studies the dynamics of electrically conducting fluids - in this case the fluid is the coronal plasma. Observed properties of the waves (e.g. period, wavelength, amplitude, temporal and spatial signatures, characteristic scenarios of the wave evolution, combined with a theoretical modelling of the wave phenomena, may reflect physical parameters of the corona which are not accessible in situ, such as the coronal magnetic field strength and Alfvén velocity and coronal dissipative coefficients. Originally, the method of MHD coronal seismology was suggested by Y. Uchida in 1970 for propagating waves, and B. Roberts et al. in 1984 for standing waves, but was not practically applied until the late 90s due to a lack of necessary observational resolution. Philosophically, coronal seismology is similar to the Earth's seismology, helioseismology, and MHD spectroscopy of laboratory plasma devices. In all these approaches, waves of various kind are used to probe a medium.
Neptune is the eighth and farthest known planet from the Sun. It is the fourth-largest planet in the Solar System by diameter, the third-most-massive planet, and the densest giant planet. It is 17 times the mass of Earth. Compared to its fellow ice giant Uranus, Neptune is slightly more massive, but denser and smaller. Being composed primarily of gases and liquids, it has no well-defined solid surface, and orbits the Sun once every 164.8 years at an orbital distance of 30.1 astronomical units. It is named after the Roman god of the sea and has the astronomical symbol , representing Neptune's trident.
Interface Region Imaging Spectrograph (IRIS), also called Explorer 94 and SMEX-12, is a NASA solar observation satellite. The mission was funded through the Small Explorer program to investigate the physical conditions of the solar limb, particularly the interface region made up of the chromosphere and transition region. The spacecraft consists of a satellite bus and spectrometer built by the Lockheed Martin Solar and Astrophysics Laboratory (LMSAL), and a telescope provided by the Smithsonian Astrophysical Observatory (SAO). IRIS is operated by LMSAL and NASA's Ames Research Center.
The High Resolution Coronal Imager (Hi-C) is a sub-orbital telescope designed to take high-resolution images of the Sun's corona. As of 2020 it has been launched three times, but only the first and the third launches, on July 11, 2012, and May 29, 2018, resulted in a successful mission. It was launched aboard a Black Brant sounding rocket from White Sands Missile Range, New Mexico. The images taken were the highest resolution photos ever of the Sun's corona.
The Heliophysics Science Division of the Goddard Space Flight Center (NASA) conducts research on the Sun, its extended Solar System environment, and interactions of Earth, other planets, small bodies, and interstellar gas with the heliosphere. Division research also encompasses geospace—Earth's uppermost atmosphere, the ionosphere, and the magnetosphere—and the changing environmental conditions throughout the coupled heliosphere.
Craig Edward DeForest is an American heliophysicist and the former Chair of the American Astronomical Society's Solar Physics Division. He is Director of the Department of Solar and Heliospheric Physics at the Boulder, Colorado offices of the Southwest Research Institute and holds an adjunct faculty position at the University of Colorado, Boulder. His wide-ranging contributions to the field of experimental astrophysics of the Sun include: early work on the MSSTA, a sounding rocket that prototyped modern normal-incidence EUV optics such as are used on the Solar Dynamics Observatory; his discovery of sound waves in the solar corona in 1998; standardization of computer vision techniques that are used to measure and track magnetic fields on the solar surface; co-invention with colleague Charles Kankelborg of the fluxon semi-Lagrangian approach to numerical MHD modeling; and pioneering work on quantitative remote sensing of the solar wind via Thomson scattered light.
Katharine Reeves is an astronomer and solar physicist who works at the Center for Astrophysics | Harvard & Smithsonian (CfA). She is known for her work on high temperature plasmas in the solar corona, and measurement/analysis techniques to probe the physics of magnetic reconnection and thermal energy transport during solar flares; these are aspects of the coronal heating problem that organizes a large part of the field. She has a strong scientific role in multiple NASA and international space missions to observe the Sun: Hinode ; IRIS ; SDO; Parker Solar Probe; and suborbital sounding rockets including the MaGIXS and Hi-C FLARE high-resolution spectral imaging packages.
Student Nitric Oxide Explorer, was a NASA small scientific satellite which studied the concentration of nitric oxide in the thermosphere. It was launched in 1998 as part of NASA's Explorer program. The satellite was the first of three missions developed within the Student Explorer Demonstration Initiative (STEDI) program funded by the NASA and managed by the Universities Space Research Association (USRA). STEDI was a pilot program to demonstrate that high-quality space science can be carried out with small, low-cost free-flying satellites on a time scale of two years from go-ahead to launch. The satellite was developed by the University of Colorado Boulder's Laboratory for Atmospheric and Space Physics (LASP) and had met its goals by the time its mission ended with reentry in December 2003.
Ralph D. Lorenz is a planetary scientist and engineer at the Johns Hopkins Applied Physics Lab. whose research focuses on understanding surfaces, atmospheres, and their interactions on planetary bodies, especially Titan, Venus, Mars, and Earth. He currently serves as Mission Architect of Dragonfly, NASA's fourth selected New Frontiers mission, and as participating scientist on Akatsuki and InSight. He is a Co-Investigator on the SuperCam instrument on the Perseverance rover, responsible for interpreting data from its microphone. He leads the Venus Atmospheric Structure Investigation on the DAVINCI Discovery mission to Venus. He is the recipient of the 2020 International Planetary Probe Workshop (IPPW) Al Seiff memorial award, and the 2022 American Geophysical Union's Fred Whipple Award for contributions to planetary science.
Gordon Dean Holman is an emeritus research astrophysicist at the National Aeronautics and Space Administration's (NASA’s) Goddard Space Flight Center in Greenbelt, Maryland. His research mostly focused on obtaining an understanding of high-energy radiation from astronomical objects. This radiation cannot be observed from Earth's surface, but is observed with instruments on satellites launched to orbits above Earth's atmosphere. It is primarily emitted by high-energy electrons interacting with ions. These electrons also emit radiation at radio frequencies which is observed from Earth's surface. Consequently, these observations from space and radio telescopes provide a view of hot gas and energetic particles in the Universe that could not otherwise be obtained. Holman has specialized in the interpretation of these observed emissions to determine the origin and evolution of this hot gas and energetic particles. He has been described as "not just a theorist, he also looks at the data".
References
- ↑ De Pontieu, B.; et al. (2011). ""The Origins of Hot Plasma in the Solar Corona"". Science. 331 (6013): 55. doi:10.1126/science.1197738.
- ↑ De Pontieu, B.; et al. (2007). ""Chromospheric Alfvénic Waves Strong Enough to Power the Solar Wind"". Science. 318 (58556): 1574. doi:10.1126/science.1151747.
- ↑ De Pontieu, B.; et al. (2014). "The Interface Region Imaging Spectrograph (IRIS)". Solar Physics. 289: 2733. doi:10.1007/s111207-014-0485-y.
- ↑ ""Multi-Slit Solar Explorer (MUSE) Mission Selected as Medium-Class Explorer"". science.msfc.nasa.gov. Retrieved 2023-04-03.
| Authority control databases: Academics |
|---|
 | This article about a physicist is a stub. You can help Wikipedia by expanding it. |