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Global upper-atmospheric heating on Jupiter by the polar aurorae
High-resolution observations confirm that Jupiter’s global upper atmosphere is heated by transport of energy from the polar aurora.
- J. O’Donoghue
- , L. Moore
- & C. Tao
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Letter |
Electron magnetic reconnection without ion coupling in Earth’s turbulent magnetosheath
Observations of electron-scale current sheets in Earth’s turbulent magnetosheath reveal electron reconnection without ion coupling, contrary to expectations from the standard model of magnetic reconnection.
- T. D. Phan
- , J. P. Eastwood
- & W. Magnes
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Letter |
Pulsating aurora from electron scattering by chorus waves
High-angular-resolution measurements allow the direct observation of the scattering of energetic electrons by chorus waves in the magnetosphere, which causes quasiperiodic electron precipitation that gives rise to pulsating aurorae.
- S. Kasahara
- , Y. Miyoshi
- & I. Shinohara
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Letter |
Measurement of electrons from albedo neutron decay and neutron density in near-Earth space
Electrons derived from cosmic rays become trapped in the radiation belts that surround Earth, but how the electrons are generated has been uncertain; new measurements confirm the involvement of neutron decay.
- Xinlin Li
- , Richard Selesnick
- & Michael A. Temerin
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Letter |
Discrete and broadband electron acceleration in Jupiter’s powerful aurora
The process that generates Earth’s most intense aurora is found to occur at Jupiter, but is of only secondary importance in generating Jupiter’s much more powerful aurora.
- B. H. Mauk
- , D. K. Haggerty
- & P. Valek
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Letter |
Magnetospherically driven optical and radio aurorae at the end of the stellar main sequence
Radio and optical spectroscopic observations of a brown dwarf reveal auroral emissions powered by magnetospheric currents, showing that aurorae may be a signature of magnetospheres much larger than those observed in our Solar System.
- G. Hallinan
- , S. P. Littlefair
- & A. Antonova
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Letter |
Global-scale coherence modulation of radiation-belt electron loss from plasmaspheric hiss
Simultaneous measurements of structured radiation-belt electron losses (in the form of bremsstrahlung X-rays) and plasmaspheric hiss (which causes the losses) reveal that the loss dynamics is coherent with the hiss dynamics on spatial scales comparable to the size of the plasmasphere.
- A. W. Breneman
- , A. Halford
- & C. A. Kletzing
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Letter |
An impenetrable barrier to ultrarelativistic electrons in the Van Allen radiation belts
Analysis of data obtained by probe spacecraft shows that ultrarelativistic electrons in the Van Allen radiation belts are prevented from entering a sharply defined region around the Earth, possibly owing to a combination of slow natural inward diffusion and pitch angle scattering.
- D. N. Baker
- , A. N. Jaynes
- & L. J. Lanzerotti
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Letter |
Rotationally driven ‘zebra stripes’ in Earth’s inner radiation belt
The distributions of energetic electrons across the entire spatial extent of Earth’s inner radiation belt are found to be organized in regular, highly structured and unexpected ‘zebra stripes’, produced by Earth’s rotation.
- A. Y. Ukhorskiy
- , M. I. Sitnov
- & B. H. Mauk
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Letter |
Rapid local acceleration of relativistic radiation-belt electrons by magnetospheric chorus
High-resolution measurements of electrons obtained by satellite during the geomagnetic storm of 9 October 2012 together with a data-driven global wave model are analysed to show that scattering by a magnetospheric electromagnetic emission, known as ‘chorus’, can explain the temporal evolution of the observed increase in relativistic electron flux.
- R. M. Thorne
- , W. Li
- & S. G. Kanekal
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Letter |
The domination of Saturn’s low-latitude ionosphere by ring ‘rain’
A pattern of features is detected, superposed on Saturn’s low-latitude infrared glow, that implies the transfer of charged species derived from water (ring ‘rain’) from the ring plane to the ionosphere, ultimately leading to the global modulation of upper atmospheric chemistry.
- J. O’Donoghue
- , T. S. Stallard
- & J. S. D. Blake
-
News & Views |
Geomagnetism under scrutiny
New calculations show that the electrical resistance of Earth's liquid-iron core is lower than had been thought. The results prompt a reassessment of how the planet's magnetic field has been generated and maintained over time. See Letter p.355
- Bruce Buffett
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News |
Sunny outlook for space weather forecasters
Companies seek to sell tailor-made predictions of geomagnetic storms to airlines and electricity suppliers.
- Eric Hand
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Letter |
Abrupt acceleration of a ‘cold’ ultrarelativistic wind from the Crab pulsar
Observations of γ-rays from the Crab pulsar suggest that the energy of the pulsar wind changes from electromagnetic to kinetic over a relatively short distance close to the light cylinder of the pulsar.
- F. A. Aharonian
- , S. V. Bogovalov
- & D. Khangulyan
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Letter |
Generation of scaled protogalactic seed magnetic fields in laser-produced shock waves
Experimental simulations of galaxy-forming conditions using lasers show that the Biermann battery generates seed magnetic fields, which turbulence can amplify to affect galaxy evolution.
- G. Gregori
- , A. Ravasio
- & F. Miniati
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Letter |
A current filamentation mechanism for breaking magnetic field lines during reconnection
- H. Che
- , J. F. Drake
- & M. Swisdak
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News |
Model stars set to explode
Realistic computational models of supernovae might soon solve a long-standing mystery.
- Eric Hand
Resolved imaging confirms a radiation belt around an ultracool dwarf