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相关论文: Striated AKR Emission: A Remote Tracer of Ion Soli…

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The Cluster Wideband Data instrument has been used to determine the locations of auroral kilometric radiation (AKR) using very long baseline interferometry. The technique involves cross-correlating individual AKR bursts from all six Cluster…

天体物理学 · 物理学 2015-06-24 R. L. Mutel , D. A. Gurnett , I. W. Christopher , J. Pickett , M. Schlax

We calculate growth rates and corresponding gains for RX and LO mode radiation associated with the cyclotron maser instability for parameterized horseshoe electron velocity distributions. The velocity distribution function was modeled to…

天体物理学 · 物理学 2015-05-13 R. L. Mutel , W. M. Peterson , T. R. Jaeger , J. D. Scudder

Recent theoretical work shows that "electron exhausts", elongated regions of depleted electron density shown by PIC codes to be generated in collisionless reconnection, can in principle become sources of X-mode Auroral Kilometric Radiation…

空间物理 · 物理学 2018-03-30 R. A. Treumann , W. Baumjohann , J. LaBelle

Data collected with Polrad swept frequency analyzer during almost 2.5 years of Interball-2 mission are used to investigate the directivity properties of AKR observed in the Northern Hemisphere. In contrast with the previous, mostly…

天体物理学 · 物理学 2015-06-24 R. Schreiber

Electron holes are suggested to be an important source for generation of electron-cyclotron maser radiation. We demonstrate that electron holes generated in a ring-horseshoe distribution in the auroral-kilometric radiation source region…

空间物理 · 物理学 2012-01-17 R. A. Treumann , W. Baumjohann , R. Pottelette

We focus on detecting and studying quasi-periodic propagating features that have been interpreted both in terms of slow magneto-acoustic waves and of high speed upflows. We analyze long duration spectroscopic observations of the on-disk…

太阳与恒星天体物理 · 物理学 2012-09-27 G. R. Gupta , L. Teriaca , E. Marsch , S. K. Solanki , D. Banerjee

Solar radio spikes are short duration and narrow bandwidth fine structures in dynamic spectra observed from GHz to tens of MHz range. Their very short duration and narrow frequency bandwidth are indicative of sub-second small-scale energy…

太阳与恒星天体物理 · 物理学 2021-08-31 Daniel L. Clarkson , Eduard P. Kontar , Mykola Gordovskyy , Nicolina Chrysaphi , Nicole Vilmer

Drift pairs are an unusual type of fine structure sometimes observed in dynamic spectra of solar radio emission. They appear as two identical short narrowband drifting stripes separated in time; both positive and negative frequency drifts…

太阳与恒星天体物理 · 物理学 2019-10-23 Alexey Kuznetsov , Eduard Kontar

This Brief Communication presents a quantitative investigation for the effect of electron holes on electron-cyclotron maser (ECM) driven by horseshoe distributions. The investigation is based on an integrated distribution function for the…

等离子体物理 · 物理学 2016-12-21 G. Q. Zhao , Y. H. Chu , H. Q. Feng , D. J. Wu

On 17 October 2008, the Cassini spacecraft crossed the southern sources of Saturn kilometric radiation (SKR), while flying along high-latitude nightside magnetic field lines. In situ measurements allowed us to characterize for the first…

地球与行星天体物理 · 物理学 2011-01-21 L. Lamy , P. Schippers , P. Zarka , B. Cecconi , C. Arridge , M. K. Dougherty , P. Louarn , N. Andre , W. S. Kurth , R. L. Mutel , D. A. Gurnett , A. J. Coates

Since the early 1980s, decimetric spike bursts have been attributed to electron cyclotron maser emission (ECME) by the electrons that produce hard X-ray bursts as they precipitate into the chromosphere in the impulsive phase of a solar…

太阳与恒星天体物理 · 物理学 2016-11-15 D. B. Melrose , M. S. Wheatland

Narrow band bursts appear on dynamic spectra from microwave to decametric frequencies as fine structures with very small duration and bandwidth. They are thought to mark small scale magnetic reconnection. We analyzed 27 metric type-IV…

太阳与恒星天体物理 · 物理学 2016-01-27 C. Bouratzis , A. Hillaris , C. E. Alissandrakis , P. Preka-Papadema , X. Moussas , C. Caroubalos , P. Tsitsipis , A. Kontogeorgos

Simultaneous observations of AKR emission using the four-spacecraft Cluster array were used to make the first direct measurements of the angular beaming patterns of individual bursts. By comparing the spacecraft locations and AKR burst…

天体物理学 · 物理学 2015-05-13 R. L. Mutel , I. W. Christopher , J. S. Pickett

Intensity scintillations of cosmic radio sources are used to study astrophysical plasmas like the ionosphere, the solar wind, and the interstellar medium. Normally these observations are relatively narrow band. With Low Frequency Array…

Auroral kilometric radiation (AKR) is the paradigm of intense radio emission from planetary magnetospheres. Being close to the electron gyro frequency and/or its lower harmonics, its observation indicates the non-thermal state of the source…

空间物理 · 物理学 2023-02-07 W. Baumjohann , R. A. Treumann

Solar radio emission features a large number of fine structures demonstrating great variability in frequency and time. We present spatially resolved spectral radio observations of type IIIb bursts in the $30-80$ MHz range made by the Low…

太阳与恒星天体物理 · 物理学 2018-08-22 I. N. Sharykin , E. P. Kontar , A. A. Kuznetsov

The iron K$\alpha$ line commonly observed in the X-ray spectrum of both stellar-mass and supermassive black hole candidates is produced by the illumination of a cold accretion disk by a hot corona. In this framework, the activation of a new…

广义相对论与量子宇宙学 · 物理学 2015-05-18 Jiachen Jiang , Cosimo Bambi , James F. Steiner

Recent infrared (IR) observations of the center of our Galaxy indicate that the supermassive black hole source Sgr A* is strongly variable in the IR. The timescale for the variability, $\sim 30$ min, is comparable to that of the X-ray…

天体物理学 · 物理学 2009-11-10 Feng Yuan , Eliot Quataert , Ramesh Narayan

Variability of radio-emitting active galactic nuclei can be used to probe both intrinsic variations arising from shocks, flares, and other changes in emission from regions surrounding the central supermassive black hole, as well as…

高能天体物理现象 · 物理学 2015-01-21 Hayley Bignall , Steve Croft , Talvikki Hovatta , Jun Yi Koay , Joseph Lazio , Jean-Pierre Macquart , Cormac Reynolds

We investigate the kinematic properties of Galactic HII regions using radio recombination line (RRL) emission detected by the Australia Telescope Compact Array (ATCA) at 4-10 GHz and the Jansky Very Large Array (VLA) at 8-10 GHz. Our HII…

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