Review of Kilometric Continuum

Hashimoto, K.; Green, J.L.; Anderson, R. R.; Matsumoto, Hiroshi

doi:10.1007/3-540-33203-0_2

Cited by 14 publications

(17 citation statements)

References 42 publications

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“…In the history of Japanese scientific spacecraft, the GEOTAIL mission is one of the most important projects investigating the phenomena in the earth's magnetosphere, by which so many new findings and paradigms were introduced by combining observation, computer simulations and theoretical studies. The WFC onboard SELENE is expected to clarify the detailed features of the wave phenomena observed by PWI instruments (Matsumoto et al, 1994a) on board the GEOTAIL spacecraft, such as Auroral Kilometric Radiation (AKR) (Murata et al, 1997;, nonthermal continuum and kilometric continuum (KC) (Hashimoto et al, 1999(Hashimoto et al, , 2005(Hashimoto et al, , 2006, continuum enhancement , low-frequency bursts (Anderson et al, 1997), electrostatic solitary wave (ESW) (Matsumoto et al, 1994b), narrowband electrostatic noise (NEN) , f p and 2 f p emissions (Kasaba et al, 2000), and solar radio emissions (Kasahara et al, 2001), among others. Emissions with frequencies higher than the maximum plasma frequency of the magnetosheath (about 30 kHz), such as AKR, KC, and continuum enhancement, and type II and III solar bursts are observed both inside and outside the magnetosphere.…”

Section: Scientific Objectivesmentioning

confidence: 99%

Plasma wave observation using waveform capture in the Lunar Radar Sounder on board the SELENE spacecraft

et al. 2008

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The waveform capture (WFC) instrument is one of the subsystems of the Lunar Radar Sounder (LRS) on board the SELENE spacecraft. By taking advantage of a moon orbiter, the WFC is expected to measure plasma waves and radio emissions that are generated around the moon and/or that originated from the sun and from the earth and other planets. It is a high-performance and multifunctional software receiver in which most functions are realized by the onboard software implemented in a digital signal processor (DSP). The WFC consists of a fastsweep frequency analyzer (WFC-H) covering the frequency range from 1 kHz to 1 MHz and a waveform receiver (WFC-L) in the frequency range from 10 Hz to 100 kHz. By introducing the hybrid IC called PDC in the WFC-H, we created a spectral analyzer with a very high time and frequency resolution. In addition, new techniques such as digital filtering, automatic filter selection, and data compression are implemented for data processing of the WFC-L to extract the important data adequately under the severe restriction of total amount of telemetry data. Because of the flexibility of the instruments, various kinds of observation modes can be achieved, and we expect the WFC to generate many interesting data.

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Section: Scientific Objectivesmentioning

confidence: 99%

Plasma wave observation using waveform capture in the Lunar Radar Sounder on board the SELENE spacecraft

et al. 2008

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“…When the Z-mode waves encounter the layer with ω = ω pe or the radio window, a part of the wave energy is converted into the LO-mode waves with the wave frequency equal to the local plasma frequency ω pe at the radio window and escape to free space with a beaming angle of α LMCT = ±tan −1 ω ce ω pe with respect to the magnetic equator, where ω ce is the electron cyclotron frequency (Jones et al, 1987). Previous observations and theories have been reviewed in detail by Hashimoto et al (2005Hashimoto et al ( , 2006. Grimald et al (2007) investigated a quantitative test of Jones NTC beaming theory by using CLUSTER constellation.…”

Section: Introductionmentioning

confidence: 99%

Simulation of mode conversion process from upper-hybrid waves to LO-mode waves in the vicinity of the plasmapause

et al. 2010

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Abstract. In order to clarify the role of the mode conversion process in the generation mechanism of LO-mode waves in the equatorial region of the plasmasphere, we have investigated the linear mode conversion process among upper-hybrid-resonance (UHR)-mode, Z-mode and LOmode waves by a numerical simulation solving Maxwell's equations and the equation of motion of a cold electron fluid. The wave coupling process occurring in the cold magnetized plasma are examined in detail. In order to give a realistic initial plasma condition in the numerical experiments, we use initial parameters inferred from observation data obtained around the generation region of LO-mode waves obtained by the Akebono satellite. A density gradient is estimated from the observed UHR frequency, and wave normal angles are estimated from the dispersion relation of cold plasma by comparing observed wave electric fields. Then, we perform numerical experiments of mode conversion processes using the density gradient of background plasma and the wave normal angle of incident upper hybrid mode waves determined from the observation results. We found that the characteristics of reproduced LO-mode waves in each simulation run are consistent with observations.

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“…The fundamental characteristics of observed continuum radiation have been explained by the proposed mechanism (Jones, 1980(Jones, , 1987. Observations and theories have been summarized by Hashimoto et al (2006).…”

Section: Introductionmentioning

confidence: 99%

Simulation of mode conversion from UHR-mode wave to LO-mode wave in an inhomogeneous plasma with different wave normal angles

et al. 2009

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We have investigated a linear mode conversion process among UHR-mode, Z-mode, and LO-mode waves by a computer simulation solving Maxwell's equations and the motion of a cold electron fluid. The characteristics of the wave coupling process occurring in the cold magnetized plasma were examined in detail for the case of an inhomogeneity of plasma density lying perpendicular to the ambient magnetic field. The dependence of the conversion efficiency on the incident wave normal angle, wave frequency, background plasma frequency, and steepness of density gradient was studied. The results show that an efficient mode conversion occurred in the conversion process from Z-mode to LO-mode waves rather than from the coupling between UHR-mode to LOmode waves. They also show that the highest conversion efficiency was obtained under the specific condition of the wave normal angle for the incident waves. In the specific case of such critical wave normal angles, we found that perpendicular components of refractive indexes became zero at the site of mode conversion, which is consistent with previously published results. We also show that the range of the critical normal angle varied depending on both the plasma frequency and the wave frequency. The simulation results also reveal that, when the steepness of the density gradient was taken into consideration, efficient mode conversion could be expected even in the case of the mismatch of the refractive indexes preventing the close coupling of plasma waves.

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Review of Kilometric Continuum

Cited by 14 publications

References 42 publications

Plasma wave observation using waveform capture in the Lunar Radar Sounder on board the SELENE spacecraft

Plasma wave observation using waveform capture in the Lunar Radar Sounder on board the SELENE spacecraft

Simulation of mode conversion process from upper-hybrid waves to LO-mode waves in the vicinity of the plasmapause

Simulation of mode conversion from UHR-mode wave to LO-mode wave in an inhomogeneous plasma with different wave normal angles

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