Striated drifting auroral kilometric radiation bursts: Possible stimulation by upward traveling EMIC waves

Menietti, J. D.; Mutel, R. L.; Santolı́k, O.; Scudder, J. D.; Christopher, I. W.; Cook, J. M.

doi:10.1029/2005ja011339

Cited by 10 publications

(21 citation statements)

References 45 publications

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“…This modulation is a function of electron energy and frequency (Figures 8 and 9) and should propagate along the magnetic field line at the group velocity of the EMIC waves producing a frequency‐drifting signature [cf. Menietti et al , 2006]. Growth of AKR will be strongest in a small range of frequencies near local f ce along the magnetic field line.…”

Section: Discussionmentioning

confidence: 99%

Modulation of the growth of auroral kilometric radiation by electromagnetic ion cyclotron waves

Xin

Menietti

2007

J. Geophys. Res.

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[1] The role of electromagnetic ion cyclotron (EMIC) waves in the stimulation of auroral kilometric radiation is addressed in this study. Observations of the modulation of electron flux and energy due to EMIC/electrostatic ion cyclotron waves within the auroral kilometric radiation (AKR) source region have been reported in the past. These modulations produce in turn oscillations of the electron phase space density and therefore lead to fluctuations of AKR growth rate that may translate along the magnetic field line at the group velocity of the stimulating waves. For a model electron ''horseshoe'' distribution function, we use the theory of the cyclotron maser instability to investigate how this process might influence the AKR wave spectrum and fine structure.

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Section: Discussionmentioning

confidence: 99%

Modulation of the growth of auroral kilometric radiation by electromagnetic ion cyclotron waves

Xin

Menietti

2007

J. Geophys. Res.

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“…Solitary structures have recently been suggested as the cause of frequency fine structure seen in dynamical spectra of AKR radiation [ Pottelette et al , 2001, 2003; Pottelette and Treumann , 2005; Mutel et al , 2006]. We also briefly consider the effect of electromagnetic ion cyclotron (EMIC) waves, which have been associated with stimulation of AKR [ Menietti et al , 2006; Xin and Menietti , 2007].…”

Section: Growth Rate Modification Caused By Solitary Structures and Ementioning

confidence: 99%

“…Gurnett and Anderson [1981] first suggested that the drifting narrowband features were the result of a propagating disturbance which triggers narrowband AKR emission at the local cyclotron frequency. Several recent papers ascribe AKR fine structure to solitary structures such as electron holes [ Pottelette et al , 2003], ion holes [ Mutel et al , 2006], tripolar structures [ Pottelette and Treumann , 2005], or to electromagnetic ion cyclotron waves [ Menietti et al , 2006; Xin and Menietti , 2007]. These waves propagate along (or obliquely to) field lines and are thought to modify the electron distribution so as to enhance the CMI growth rate.…”

Section: Introductionmentioning

confidence: 99%

Dependence of cyclotron maser instability growth rates on electron velocity distributions and perturbation by solitary waves

et al. 2007

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[1] We calculate growth rates and corresponding gains for right-hand circularly polarized extraordinary (RX) and left-hand ordinary circularly polarized (LO) mode radiation associated with the cyclotron maser instability (CMI) for parameterized horseshoe electron velocity distributions. The velocity distribution function was modeled to closely fit the electron distribution functions observed in the auroral cavity. We systematically varied the model parameters as well as the propagation direction to study the dependence of growth rates on model parameters. The growth rate depends strongly on loss cone opening angle, which must be less than 90°for significant CMI growth. The growth rate is sharply peaked for perpendicular radiation (k k = 0), with a full width at half maximum 1.7°, in good agreement with observed k-vector orientations and numerical simulations. The fractional bandwidth varied between 10 À4 and 10 À2 , depending most strongly on propagation direction. This range encompasses nearly all observed fractional auroral kilometric radiation (AKR) burst bandwidths. We find excellent agreement between the computed RX mode emergent intensities and observed AKR intensities assuming convective growth length L c % 20-40 km and group speed 0.15c. The only computed LO mode growth rates compatible observed LO mode radiation levels occurred for number densities more than 100 times the average energetic electron densities measured in auroral cavities. This implies that LO mode radiation is not produced directly by the CMI mechanism but more likely results from mode conversion of RX mode radiation. We find that perturbation of the model velocity distribution by large ion solitary waves (ion holes) can enhance the growth rate by a factor of 2-4. This will result in a gain enhancement more than 40 dB depending on the convective growth length within the structure. Similar enhancements may be caused by strong electromagnetic ion cyclotron waves.

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“…Pottelette et al (2001) presented a theory based on electron holes to explain typical or random fine structure of AKR. Menietti et al (2006) pointed out that electrons holes are more abundantly observed in downward current regions, so they would be less likely to be responsible for generating AKR emissions, which is thought to be produced in upward fieldaligned current regions. Mutel et al (2006) proposed that ion holes, rather than electron holes or tripolar structures, are the source of AKR ordered fine structure.…”

Section: Betatron and Stochastic Accelerationmentioning

confidence: 99%

“…Mutel et al (2006) proposed that ion holes, rather than electron holes or tripolar structures, are the source of AKR ordered fine structure. Analyzing Cluster WBD observations of ordered AKR fine structure and electron distributions taken by the Polar HYDRA instrument near magnetic conjunction, Menietti et al (2006) found that the unstable electron horseshoe distributions in/near the AKR source region can also produce electromagnetic ion cyclotron (EMIC) waves. They proposed that ordered AKR fine structures can be stimulated by upward propagating EMIC waves.…”

Section: Betatron and Stochastic Accelerationmentioning

confidence: 99%

Multipoint observations of plasma phenomena made in space by Cluster

et al. 2015

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Plasmas are ubiquitous in nature, surround our local geospace environment, and permeate the universe. Plasma phenomena in space give rise to energetic particles, the aurora, solar flares and coronal mass ejections, as well as many energetic phenomena in interstellar space. Although plasmas can be studied in laboratory settings, it is often difficult, if not impossible, to replicate the conditions (density, temperature, magnetic and electric fields, etc.) of space. Single-point space missions too numerous to list have described many properties of near-Earth and heliospheric plasmas as measured both in situ and remotely (see http://www.nasa.gov/missions/#.U1mcVmeweRY for a list of NASA-related missions). However, a full description of our plasma environment requires three-dimensional spatial measurements. Cluster is the first, and until data begin flowing from the Magnetospheric Multiscale Mission (MMS), the only mission designed to describe the three-dimensional spatial structure of plasma phenomena in geospace. In this paper, we concentrate on some of the many plasma phenomena that have been studied using data from Cluster. To date, there have been more than 2000 refereed papers published using Cluster data but in this paper we will, of necessity, refer to only a small fraction of the published work. We have focused on a few basic plasma phenomena, but, for example, have not dealt with most of the vast body of work describing dynamical phenomena in Earth's magnetosphere, including the dynamics of current sheets in Earth's magnetotail and the morphology of the dayside high latitude cusp. Several review articles and special publications are available that describe aspects of that research in detail and interested readers are referred to them (see for example, Escoubet et al.

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Striated drifting auroral kilometric radiation bursts: Possible stimulation by upward traveling EMIC waves

Cited by 10 publications

References 45 publications

Modulation of the growth of auroral kilometric radiation by electromagnetic ion cyclotron waves

Modulation of the growth of auroral kilometric radiation by electromagnetic ion cyclotron waves

Dependence of cyclotron maser instability growth rates on electron velocity distributions and perturbation by solitary waves

Multipoint observations of plasma phenomena made in space by Cluster

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