Philippa Browning | |
---|---|
Born | Philippa K. Browning |
Education | Millfield [1] |
Alma mater | University of Cambridge (BA) University of St Andrews (PhD) |
Awards | Chapman Medal (2016) |
Scientific career | |
Fields | Astrophysics Solar physics |
Institutions | University of Manchester University of Manchester Institute of Science and Technology |
Thesis | Inhomogeneous magnetic fields in the solar atmosphere |
Doctoral advisor | Eric Priest [2] |
Website | www |
Philippa K. Browning FInstP is a Professor of Astrophysics in the Jodrell Bank Centre for Astrophysics at the University of Manchester. [3] She specialises in the mathematical modelling of fusion and solar plasmas. [4]
Browning was educated at Millfield [1] and studied the Mathematical Tripos at the University of Cambridge, graduating in 1979. [5] She completed Part III of the Mathematical Tripos in 1980. [6] She was inspired by Yuri Gagarin to work in astrophysics. [7] [8] For her graduate studies Browning joined the University of St Andrews working with Eric Priest. [9] [10] She submitted her thesis on Inhomogeneous Magnetic Fields in the Solar Atmosphere in 1984. [2]
After completing her PhD Browning worked as a postdoctoral researcher with Eric Priest. [9] She studied coronal loops, finding they were a balance of magnetic tension forces, buoyancy and pressure gradients. [11] Her work covered the fundamentals of flux tubes. [12] Browning was appointed a lecturer at University of Manchester Institute of Science and Technology (UMIST) in 1985.[ citation needed ] She joined the University of Manchester in 2004, where she works on the interactions between plasmas and magnetic fields. [3] She is particularly interested in solar flares. [13] [14] [15] In 2009, Browning was promoted to professor at the Jodrell Bank Centre for Astrophysics. [4] She served as editor of the Journal of Geophysical Research from 2010 to 2013. [16] She contributed to the book Multi-scale Dynamical Processes in Space and Astrophysical Plasmas. [17] She continues to study coronal heating. [18] [19]
In 2013 Browning was made chair of the Institute of Physics Plasma Physics Committee and the Solar Physics Council. [20] Through the Solar Physics Council, Browning is a mentor for young solar physicists. [21] In 2014 Browning arranged two-day meeting to discuss coronal heating at the Royal Society. [22]
As of 2018 [update] Browning is working on the Solar Orbiter and Parker Solar Probe. [7] Browning has appeared at the Bluedot Festival. She discussed her work on solar flares and their interaction with the earth. [23] She has taken part in the Manchester Science Festival. [24] Browning serves on the Institute of Physics Women in Physics advisory panel. [25]
Browning was awarded the Chapman Medal by the Royal Astronomical Society in 2016. [26] [27] The medal recognised her "pioneering work on energy release by magnetic relaxation in stressed coronal magnetic fields". [28] In 2017 she was awarded a Science and Technology Facilities Council (STFC) research grant to explore particle acceleration in twisted magnetic fields. [29] She was elected a Fellow of the Institute of Physics (FInstP).[ when? ]
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 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.
A solar flare is a relatively intense, localized emission of electromagnetic radiation in the Sun's atmosphere. Flares occur in active regions and are often, but not always, accompanied by coronal mass ejections, solar particle events, and other eruptive solar phenomena. The occurrence of solar flares varies with the 11-year solar cycle.
A coronal mass ejection (CME) is a significant ejection of plasma mass from the Sun's corona into the heliosphere. CMEs are often associated with solar flares and other forms of solar activity, but a broadly accepted theoretical understanding of these relationships has not been established.
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.
Eugene Newman Parker was an American solar and plasma physicist. In the 1950s he proposed the existence of the solar wind and that the magnetic field in the outer Solar System would be in the shape of a Parker spiral, predictions that were later confirmed by spacecraft measurements. In 1987, Parker proposed the existence of nanoflares, a leading candidate to explain the coronal heating problem.
Eric Ronald Priest is Emeritus Professor at St Andrews University, where he previously held the Gregory Chair of Mathematics and a Bishop Wardlaw Professorship.
In magnetohydrodynamics (MHD), shocks and discontinuities are transition layers where properties of a plasma change from one equilibrium state to another. The relation between the plasma properties on both sides of a shock or a discontinuity can be obtained from the conservative form of the MHD equations, assuming conservation of mass, momentum, energy and of .
In solar physics, a coronal loop is a well-defined arch-like structure in the Sun's atmosphere made up of relatively dense plasma confined and isolated from the surrounding medium by magnetic flux tubes. Coronal loops begin and end at two footpoints on the photosphere and project into the transition region and lower corona. They typically form and dissipate over periods of seconds to days and may span anywhere from 1 to 1,000 megametres in length.
A stellar magnetic field is a magnetic field generated by the motion of conductive plasma inside a star. This motion is created through convection, which is a form of energy transport involving the physical movement of material. A localized magnetic field exerts a force on the plasma, effectively increasing the pressure without a comparable gain in density. As a result, the magnetized region rises relative to the remainder of the plasma, until it reaches the star's photosphere. This creates starspots on the surface, and the related phenomenon of coronal loops.
A nanoflare is a very small episodic heating event which happens in the corona, the external atmosphere of the Sun.
Supra-arcade downflows (SADs) are sunward-traveling plasma voids that are sometimes observed in the Sun's outer atmosphere, or corona, during solar flares. In solar physics, arcade refers to a bundle of coronal loops, and the prefix supra indicates that the downflows appear above flare arcades. They were first described in 1999 using the Soft X-ray Telescope (SXT) on board the Yohkoh satellite. SADs are byproducts of the magnetic reconnection process that drives solar flares, but their precise cause remains unknown.
Jiong Qiu (邱炯) is a Chinese-born American astrophysicist who won the Karen Harvey Prize for her work in solar flares.
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.
Lindsay Erin Glesener is a professor in the Institute for Astrophysics at the University of Minnesota. She is a National Science Foundation CAREER Award researcher and lead investigator on the FOXSI Sounding Rocket.
Lyndsay Fletcher is a Scottish astrophysicist at the University of Glasgow who specialises in solar flares.
SWEAP is an instrument on the unmanned space probe to the Sun, the Parker Solar Probe. The spacecraft with SWEAP on board was launched by a Delta IV Heavy on 12 August 2018 from Cape Canaveral, Florida. SWEAP includes two types of instruments, the Solar Probe Cup (SPC) and Solar Probe Analyzers (SPAN). SWEAP has four sensors overall, and is designed to take measurements of the Solar wind including electrons and ions of hydrogen (protons) and helium.
Lidia van Driel-Gesztelyi is a Hungarian solar scientist and professor of physics at the Mullard Space Science Laboratory of University College London. She also maintains affiliations with Solar and Stellar Activity Research Team at Konkoly Observatory of the Hungarian Academy of Sciences and the Space Research Laboratory (LESIA) of Paris Observatory. She has been Editor-in-Chief of the journal Solar Physics since 2005 and has served in leadership roles within the International Astronomical Union.
Solar radio emission refers to radio waves that are naturally produced by the Sun, primarily from the lower and upper layers of the atmosphere called the chromosphere and corona, respectively. The Sun produces radio emissions through four known mechanisms, each of which operates primarily by converting the energy of moving electrons into electromagnetic radiation. The four emission mechanisms are thermal bremsstrahlung (braking) emission, gyromagnetic emission, plasma emission, and electron-cyclotron maser emission. The first two are incoherent mechanisms, which means that they are the summation of radiation generated independently by many individual particles. These mechanisms are primarily responsible for the persistent "background" emissions that slowly vary as structures in the atmosphere evolve. The latter two processes are coherent mechanisms, which refers to special cases where radiation is efficiently produced at a particular set of frequencies. Coherent mechanisms can produce much larger brightness temperatures (intensities) and are primarily responsible for the intense spikes of radiation called solar radio bursts, which are byproducts of the same processes that lead to other forms of solar activity like solar flares and coronal mass ejections.
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".