Journal of Geophysical Research: Space Physics

Commentary in JGR-Space PhysicsThomsen et al. [2016] provide a new statistical analysis of nearly 8 years of Cassini Plasma Spectrometer data, revealing that hot electrons injected from Saturn's outer magnetosphere penetrate into the inner magnetosphere but only to a distinct inner edge whose location is independent of external solar wind properties. This result is fully consistent with the hypothesis that centrifugally driven interchange motion is responsible for plasma transport between inner Continue reading >

From Eos.org: Research Spotlights—The resonant vibrations of the Ross Ice Shelf in Antarctica are disturbing the atmosphere above it, creating huge ripples.Earlier this year, scientists reported mysterious waves appearing in the skies above Antarctica. These enormous ripples occur in the stratosphere and above, like mountainous swells of air that rise and fall over a period of hours.A new study by Godin and Zabotin suggests an unlikely cause: vibrations in the massive ice shelf below, whi Continue reading >

Editors’ Highlight—This paper provides new MMS observations revealing the complexity of a small-scale structure associated with a magnetosheath jet, which may advance our understanding of the origin of electron beams in the magnetosheath. Continue reading >

Editors’ Highlight—Energy conversion from the solar wind into the magnetosphere is a subject of debate in space physics, in particular the role of "Dungey convection," which is purely from magnetic distortion and supposedly does not require a plasma pressure gradient.  This paper takes aim at this "classic picture of solar wind-magnetosphere coupling" and concludes that pressure gradients are necessary and the two processes, magnetic distortion and localized plasma pressure extrema, go hand in Continue reading >

Editors’ Highlight—This paper addresses the long standing problem of robust inversion of the UV emission to yield ionospheric profiles; it represents a milestone in the development of remote sensing of the ionosphere. The extreme ultraviolet emission from the Earth's atmosphere was first demonstrated by work in the 70s by Carruthers and Paige using a lunar based UV spectrograph. Much work followed to relate the properties of the emissions to atmospheric and ionospheric state variables observed Continue reading >

From Eos.org: Research Spotlights—The long-term trend in the electron density of the ionospheric F layer may be natural, not man-made.Earth’s ionosphere is a “conducting layer” that can transmit radio signals. To ensure the reliability of these transmissions, scientists must first understand how ionospheric variations influence radio signals, and the drivers behind these variations.One hypothesis holds that long term trends in the ionosphere  relates the increase of carbon dioxide in lower laye Continue reading >

Editors’ Highlight—Dan Baker wrote a paper in Science in 2014 on the "inpenetrable barrier" at L=2.8 for the radiation belts around Earth. This new paper uses modeling to show when energetic electrons might break through that barrier.  It requires really strong and transient electric fields during highly disturbed/active times.  Continue reading >

Editors’ Highlight—The paper provides important new results about the magnetic twist present in magnetic clouds.  First, the authors developed and apply a new method to a large number of events (almost all cases presently observed by Wind spacecraft).  Second, they characterize the magnetic twist and compare their results with the few cases previously studied with other methods.  Finally, they compare their results to the present knowledge of solar observations and test the instability criteria Continue reading >

From Eos.org: Research Spotlights—Data from multiple orbiters give a clearer picture of how density and temperature interact and what that could mean for future satellite missions.If it weren’t for the exosphere—Earth’s outermost layer of atmosphere—we might all be at the mercy of the Sun’s blinding rays and other objects hurling toward us from outer space. Here, in the exosphere, the air becomes very thin, almost vacuum-like, with very few particles, as many atoms and molecules from Earth’s at Continue reading >

From Eos.org: Research Spotlights—How energetic would lightning on Venus have to be to be detected by sensors? A new model sheds light.Venus—Earth’s closest sibling—is a hellish planet with surface temperatures that swing as high as 800°F and an atmosphere that slams down with nearly 100 times the pressure at Earth’s surface. Sulfuric acid haze laces its carbon dioxide atmosphere. But whether to add lightning into the mix of inhospitable ingredients remains controversial.The debate began in Dec Continue reading >

From Eos.org: Research Spotlights—The first results from a recently launched satellite hold promise for studying solar storms, the very top of Earth’s ionosphere, and how the atmosphere is evolving.The border between Earth and space is a turbulent one: Ions from the solar wind and other forms of space weather batter Earth’s atmosphere, which is constantly churning and slowly leaking away into space.  Solar storms in particular whip the upper atmosphere into a frenzy, with potentially devastatin Continue reading >

Editors’ Highlight—The auroral red line at 630 nm is linearly polarised. The energetic electrons that cause the aurora change the magnetic field of the Earth by a small amount. Jean Lilensten and colleagues measured the angle of polarisation for the first time using data from Ny Alesund, Northern Norway. Thus they have developed a new remote-sensing technique for determining the magnetic field configuration which could have applications both for planetary science space weather studies.  Continue reading >

Editors’ Highlight—The general concept of a Spectral Kurtosis spectrometer is a powerful method be used in post-facto data analysis, and it can and has been implemented in hardware for "on the fly" data cleaning.  It is very useful in applications with heavy or restricted data streams, such as interferometers or spacecraft telemetry.  Continue reading >

From Eos.org: Research Spotlights—Polarity reversals in the solar wind magnetic field disconnect the magnetic field trailing behind Venus, allowing ions from the atmosphere to escape.Venus, unlike Earth, does not produce its own magnetic field. It does, however, have an ionosphere, which is formed when radiation from the Sun ionizes the top layers of the planet's neutral atmosphere. This ionosphere, because it is made up of charged ions, can interact with the magnetic field embedded in the sola Continue reading >

From Eos.org: Research Spotlights— Scientists investigate how dipolarization fronts in Earth’s protective magnetosphere interact with the environment around them. Earth has a substantial magnetic field called the magnetosphere, which acts as a buffer that protects the planet from sudden, incoming bursts of energy from the Sun and outer space. The magnetosphere is the result of the interaction between Earth’s magnetic field and solar wind, and its charged particles are controlled by Earth’s magn Continue reading >

Editors’ Highlight—This study shows that robust assessments of the structure and evolution of shallow submarine atmospheric loss from Mars happens via many processes, one of them is the loss of molecular oxygen ions.  These are abundant in the lower ionosphere (150 km) but their relatively heavy mass keeps them gravitationally tied to the planet.  They occasionally get pulled out to deep space, however, by the fast-moving electrons via a connection called the ambipolar ele Continue reading >

From Eos.org: Research Spotlights—Space physicists say that Pluto’s atmosphere interacts with the solar wind in a never-before-seen hybrid way, one that’s both comet-like and planet-like. Solar wind spews off from the Sun into the solar system at a supersonic 400 kilometers per second, bathing planets, asteroids, comets, and interplanetary space in a soup of mostly electrons and protons. Until recently, scientists thought Pluto’s interaction with the solar wind was more Continue reading >

From Eos.org: Research Spotlights—NASA’s latest mission to Mars has uncovered the origins of fast-moving streams of particles high above the planet, flowing against the solar wind.High above the surface of Mars’s sunlit side, protons of the solar wind begin to smash into the upper reaches of Mars’s atmosphere. NASA’s Mars Atmosphere and Volatile Evolution Mission (MAVEN) spacecraft, which arrived at the red planet in 2014, has detected mysterious beams of oxygen io Continue reading >

Joint Press Release—WASHINGTON, DC — Solar storms trigger Jupiter’s intense ‘Northern Lights’ by generating a new X-ray aurora that is eight times brighter than normal and hundreds of times more energetic than Earth’s aurora borealis, new research finds...…more Continue reading >

Editors’ Highlight—This paper shows the importance of jets (plasmoids) of the magnetosheath of Earth to the physics of the magnetopause and phenomena in the magnetosphere. Large jets are geoeffective because of the momentum and energy they carry, and small jets can penetrate the magnetopause. When studying the physics of the magnetopause these plasma entities created upstream can no longer be ignored.  Continue reading >