Jovian S-burst observations at 32 MHz

Desch, M. D.; Flagg, R. S.; May, J.

doi:10.1038/272038a0

Cited by 19 publications

(9 citation statements)

References 7 publications

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“…• At longitudes Aii I Io • 220 _ 40 ø, the observed angular thickness 8• decreases to about 0.5 ø. The observed width Ads of the scattering histogram at a fixed frequency[Desch et al, 1978;Flagg and Desch, 1979;Ellis, 1982] can be approximated by Ads=O.2fs,(17)which is consistent with (16) at Airfir • 0.2 and ir • 5 x 10 8 A. The radiation pencil beam produced by relativistic electron bunches moving along the helical field lines of B s around IFT shows similar directivity prope•ies.…”

supporting

confidence: 76%

“…Note that experimentally measured drift rates [Desch et al, 1978;Flagg and Desch, 1979;Ellis, 1982] where h s (in thousands of kilometers) and Pm (g/cm3) ß [Desch et al, 1978;Flagg and Desch, 1979;Ellis, 1982] with the magnitude of current fluctuations Air/it that was found from the measured [Ryabov, 1990b] asymmetry in the angular thicknesses • and •2 of the S emission cone.…”

Section: Bs 2 • 32 X 103h• -•'39 (24)mentioning

confidence: 93%

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Jovian S emission: Model of radiation source

Ryabov¹

1994

J. Geophys. Res.

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A physical model of the radiation source and an excitation mechanism have been suggested for the S component in Jupiter's sporadic radio emission. The model provides a unique explanation for most of the interrelated phenomena observed, allowing a consistent interpretation of the emission cone structure, behavior of the integrated radio spectrum, occurrence probability of S bursts, location and size of the radiation source, and fine structure of the dynamic spectra. The mechanism responsible for the S bursts is also discussed in connection with the L type emission. Relations are traced between parameters of the radio emission and geometry of the Io flux tube. Fluctuations in the current amplitude through the tube are estimated, along with the refractive index value and mass density of the plasma near the radiation source.

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supporting

confidence: 76%

Section: Bs 2 • 32 X 103h• -•'39 (24)mentioning

confidence: 93%

Jovian S emission: Model of radiation source

Ryabov¹

1994

J. Geophys. Res.

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“…These pulses, the duration of which varies from 1 to 200 ms, were later called S‐bursts (where S stands for “short”). Since their discovery, numerous reports on the morphology and characteristics of S‐bursts can be found in literature [e.g., Baart et al , 1966; Riihimaa , 1977; Desch et al , 1978; Ellis , 1980; Leblanc et al , 1980; Carr et al , 1983; Genova and Calvert , 1988; Dulk et al , 1992; Zarka et al , 1996; Queinnee and Zarka , 2001; Carr and Reyes , 1999]. Jovian S‐bursts can be summarized by the following characteristics: (1) the reoccurrence rate is between ∼2 and 400 Hz over intervals of a few seconds, the most probable rate being 20 Hz [ Carr and Reyes , 1999]; (2) they are narrow‐band emissions, 10s of kHz; (3) the center frequency, typically ∼20 MHz, lies between a few to ∼30 MHz with a rapid frequency drift, typically ∼18 MHz/s; (4) S‐bursts are strictly associated with Io‐dependent emission sources coming mostly from the Io B region in the Io‐Jupiter Central Meridian Longitude (CML) plane with observations also from Io A and C regions; and (5) they account for a relatively small fraction of the DAM emission: probably less than 10%.…”

Section: Introductionmentioning

confidence: 99%

Generation of short‐burst radiation through Alfvénic acceleration of auroral electrons

Ergun

Jones

et al. 2007

J. Geophys. Res.

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[1] A comparison of modeled simulation results with in situ observations is presented in an effort to better understand the generation mechanism of short-burst radiation (AKR) observed in the Alfvénic acceleration region. The simulation is performed using a linear gyrofluid Alfvén model to generate propagating inertial Alfvén waves with a test particle scheme to study the behavior of electrons under the influence of waves. The observations are taken from the wave and plasma instruments on board the Fast Auroral Snapshot (FAST) satellite. We find that single-and multiple-electron shell distributions are produced as a result of parallel electric fields generated from inertial Alfvén waves. Electrons outside the loss cone are reflected back up the flux tube because of the mirror force forming electron conics. Distributions obtained from this simulation resemble the observed electron distributions in the Alfvénic auroral acceleration region where short-burst radiations were present. Multiple-shell distributions as well as electron conics are unstable, making them candidates for triggering the electron-cyclotron maser instability. Hence we suggest that these unstable distributions, resulting from the effects of inertial Alfvén wave, could be the source of the observed short-burst radiation in the terrestrial auroral zone magnetosphere-ionosphere coupling region. We also briefly discuss the application of this general mechanism to explain the Io-associated S-bursts observed emanating from the Jovian magnetosphere.

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“…The Jovian S-bursts, or millisecond bursts, with their persistent and even predictable negative frequency drifts, are a particularly dramatic manifestation of Io-controlled emission. Observations at high frequencies (32 MHz) strongly suggest that the S-bursts are due to keV electrons that have been accelerated upward into the burst emission region from near the foot of the Io flux tube (Desch, Flagg, &May 1978).…”

Section: Introductionmentioning

confidence: 99%

Jupiter Radio Bursts and Particle Acceleration

Desch¹

1994

International Astronomical Union Colloquium

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Particle acceleration processes are important in understanding many of the Jovian radio and plasma wave emissions. However, except for the high-energy electrons that generate synchrotron emission following inward diffusion from the outer magnetosphere, acceleration processes in Jupiter's magnetosphere and between Jupiter and Io are poorly understood. We discuss very recent observations from the Ulysses spacecraft of two new Jovian radio and plasma wave emissions in which particle acceleration processes are important and have been addressed directly by complementary investigations. First, radio bursts known as quasi-periodic bursts have been observed in close association with a population of highly energetic electrons. Second, a population of much lower energy (keV range) electrons on auroral field lines can be shown to be responsible for the first observation of a Jovian plasma wave emission known as auroral hiss.

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Jovian S-burst observations at 32 MHz

Cited by 19 publications

References 7 publications

Jovian S emission: Model of radiation source

Jovian S emission: Model of radiation source

Generation of short‐burst radiation through Alfvénic acceleration of auroral electrons

Jupiter Radio Bursts and Particle Acceleration

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