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.
A rift valley is a linear shaped lowland between several highlands or mountain ranges produced by the action of a geologic rift. Rifts are formed as a result of the pulling apart of the lithosphere due to extensional tectonics. The linear depression may subsequently be further deepened by the forces of erosion. More generally the valley is likely to be filled with sedimentary deposits derived from the rift flanks and the surrounding areas. In many cases rift lakes are formed. One of the best known examples of this process is the East African Rift. On Earth, rifts can occur at all elevations, from the sea floor to plateaus and mountain ranges in continental crust or in oceanic crust. They are often associated with a number of adjoining subsidiary or co-extensive valleys, which are typically considered part of the principal rift valley geologically.
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 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.
Volcanic lightning is an electrical discharge caused by a volcanic eruption rather than from an ordinary thunderstorm. Volcanic lightning arises from colliding, fragmenting particles of volcanic ash, which generate static electricity within the volcanic plume, leading to the name dirty thunderstorm. Moist convection currents and ice formation also drive the eruption plume dynamics and can trigger volcanic lightning. Unlike ordinary thunderstorms, volcanic lightning can also occur before any ice crystals have formed in the ash cloud.
Michele Karen Dougherty is a Professor of Space Physics at Imperial College London. She is leading unmanned exploratory missions to Saturn and Jupiter and is Principal Investigator for J-MAG – a magnetometer for the European Space Agency's Jupiter Icy Moons Explorer, due for launch in April 2023.
In fluid dynamics, wave setup is the increase in mean water level due to the presence of breaking waves. Similarly, wave setdown is a wave-induced decrease of the mean water level before the waves break. For short, the whole phenomenon is often denoted as wave setup, including both increase and decrease of mean elevation. This setup is primarily present in and near the coastal surf zone. Besides a spatial variation in the (mean) wave setup, also a variation in time may be present – known as surf beat – causing infragravity wave radiation.
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.
In planetary sciences, the moment of inertia factor or normalized polar moment of inertia is a dimensionless quantity that characterizes the radial distribution of mass inside a planet or satellite. Since a moment of inertia has dimensions of mass times length squared, the moment of inertia factor is the coefficient that multiplies these.
Matthew Graham George Thaddeus Taylor is a British astrophysicist employed by the European Space Agency. He is best known to the public for his involvement in the landing on Comet 67P/Churyumov–Gerasimenko by the Rosetta mission 's Philae lander, which was the first spacecraft to land on a comet nucleus. He is Project Scientist of the Rosetta mission.
Chemical cycling describes systems of repeated circulation of chemicals between other compounds, states and materials, and back to their original state, that occurs in space, and on many objects in space including the Earth. Active chemical cycling is known to occur in stars, many planets and natural satellites.
The interchange instability, also known as the Kruskal–Schwarzchild instability or flute instability, is a type of plasma instability seen in magnetic fusion energy that is driven by the gradients in the magnetic pressure in areas where the confining magnetic field is curved.
Emma J. Bunce is a British space physicist and Professor of Planetary Plasma Physics at the University of Leicester. She holds a Royal Society Wolfson Research Merit Award. Her research is on the magnetospheres of Saturn and Jupiter. She is principal investigator (PI) of the MIXS instrument on BepiColombo, was deputy lead on the Jupiter Icy Moons Explorer proposal, and co-investigator on the Cassini–Huygens mission.
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.
Nancy U. Crooker is an American physicist and professor emerita of space physics at Boston University, Massachusetts. She has made major contributions to the understanding of geomagnetism in the Earth's magnetosphere and the heliosphere, particularly through the study of interplanetary electrons and magnetic reconnection.
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.
Patricia K. Quinn is a atmospheric chemist working at the National Oceanic and Atmospheric Agency's Pacific Marine Environmental Lab. She is known for her work on the impact of atmospheric aerosol particles on air quality and climate.
James Wynne "Jim" 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.
