Strong Langmuir turbulence with and without collapse: experimental study

Vyacheslavov, L. N.; Burmasov, V. S.; Kandaurov, I. V.; Kruglyakov, E. P.; Meshkov, O.; Попов, С. С.; Sanin, A.

doi:10.1088/0741-3335/44/12b/320

Cited by 25 publications

(11 citation statements)

References 33 publications

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“…This agrees with the computed examples. (2) The measured backscatter intensity in the down-going Langmuir channels is weaker than the up-going. Similar differences can be seen in the computed spectra.…”

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confidence: 95%

“…Lk, 94.05.Pt, 94.05.Fg, 94.20.wj Langmuir turbulence is known to occur in controlled laboratory [1,2] and space plasma experiments [3][4][5] and is thought to occur naturally in a variety of space and astrophysical plasmas, including pulsar magnetospheres [6], the solar corona [7], the interplanetary medium [8], planetary foreshocks [9], the terrestrial magnetosphere [10], and the ionosphere [11][12][13]. In its most developed form, this turbulence contains electron Langmuir modes trapped in dynamic density depressions known as cavitons [14][15][16].…”

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confidence: 99%

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Cavitating Langmuir Turbulence in the Terrestrial Aurora

et al. 2012

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Langmuir cavitons have been artificially produced in the earth's ionosphere, but evidence of naturally-occurring cavitation has been elusive. By measuring and modeling the spectra of electrostatic plasma modes, we show that natural cavitating, or strong, Langmuir turbulence does occur in the ionosphere, via a process in which a beam of auroral electrons drives Langmuir waves, which in turn produce cascading Langmuir and ion-acoustic excitations and cavitating Langmuir turbulence. The data presented here are the first direct evidence of cavitating Langmuir turbulence occurring naturally in any space or astrophysical plasma.PACS numbers: 94.05. Lk, 94.05.Pt, 94.05.Fg, 94.20.wj Langmuir turbulence is known to occur in controlled laboratory [1,2] and space plasma experiments [3][4][5] and is thought to occur naturally in a variety of space and astrophysical plasmas, including pulsar magnetospheres [6], the solar corona [7], the interplanetary medium [8], planetary foreshocks [9], the terrestrial magnetosphere [10], and the ionosphere [11][12][13]. In its most developed form, this turbulence contains electron Langmuir modes trapped in dynamic density depressions known as cavitons [14][15][16]. Cavitons have been shown to be artificially produced in the earth's ionosphere during high-power radiowave pumping experiments as deduced from radar spectra containing simultaneously-excited up and downshifted Langmuir and ion-acoustic lines plus a central peak due to cavitation [3][4][5], but evidence of naturally occurring cavitation has until now been elusive.Between 18 and 21 UT on 11 and 12 November 1999 a measurement program designed to detect both ionacoustic and Langmuir modes was run on the European Incoherent Scatter Scientific Association (EISCAT) 224-MHz radar located near Tromsø in northern Norway (local standard time in Norway is UT plus one hour). The principal objectives were to observe enhanced waves stimulated by high-power radiowave pumping, and, in the event of auroral activity, to gather data on natural energetic waves [17]. On both nights conditions were disturbed, and enhanced echoes were detected, the strongest being on 11 November between 18:18:30 and 18:21:30 UT, during the passage of an aurora through the vertically-directed radar beam. Fig. 1 presents parameters derived from the ion-acoustic backscatter between 18:15 and 18:28 UT, during the most intense auroral event. Fig. 2 shows the intensities of Langmuir and ion-acoustic backscatter as a function of height and time. The prominent features occurring between 18:18:30 and 18:20:30 UT and at 18:23:30 UT near 300 and 250 km altitude, respectively, are backscatter associated with the aurora, and are the most energetic natural events observed on either night. Two other events occurred later that evening and two more on the following evening. Weak ion-acoustic enhancements occurred during each event; the Langmuir enhancements, however, are always stronger. Fig. 3 shows up and down-shifted spectral lines, or "shoulders", which are produced by Doppler-...

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Cavitating Langmuir Turbulence in the Terrestrial Aurora

et al. 2012

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“…(e.g., Rowland et al, 1981b;Shapiro and Shevchenko, 1984;Robinson, 1997). The basic signatures of the SLT development in various beam-plasma systems have been observed in laboratory experiments (e.g., Cheung et al, 1982;Karfidov and Lukina, 1997;Robinson, 1997;Vyacheslavov et al, 2002).…”

Section: Nonlinear Effectsmentioning

confidence: 98%

Artificial Aurora Experiments and Application to Natural Aurora

Mishin

2019

Front. Astron. Space Sci.

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A review is given of the effects observed during injections of powerful electron beams from sounding rockets into the upper atmosphere. Data come from in situ particle and wave measurements near a beam-emitting rocket and ground-based optical, wideband radiowave, and radar observations. The overall data cannot be explained solely by collisional degradation of energetic electrons but require collisionless beam-plasma interactions (BPI) be taken into account. The beam-plasma discharge theory describes the features of the region near a beam-emitting rocket, where the beam-excited plasma waves energize plasma electrons, which then ignite the discharge. The observations far beneath the rocket reveal a double-peak structure of artificial auroral rays, which can be understood in terms of the beam-excited strong Langmuir turbulence being affected by collisions of ionospheric electrons. This leads to the enhanced energization of ionospheric electrons in a narrow layer termed the plasma turbulence layer (PTL), which explains the upper peak. Similar double-peak structures or a sharp upper boundary in rayed auroral arcs have been observed in the auroral ionosphere by optical, radar, and rocket observations, and called Enhanced Aurora. A striking resemblance between Enhanced and Artificial Aurora altitude profiles indicates that they are created by the above BPI process which results in the PTL.

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“…It is important to note that, from a broader perspective, Langmuir turbulence in the strongly nonlinear regime has been the subject of a huge number of theoretical and experimental studies [61,62], in particular in the original context of hydrodynamics [62][63][64][65], or in controlled laboratory [66,67] and space plasma experiments [68][69][70]. Furthermore, evidence of cavitating Langmuir turbulence has been recently shown to occur in natural Earth's aurora driven by solar wind [71].…”

Section: Introductionmentioning

confidence: 99%

Weak Langmuir optical turbulence in a fiber cavity

Garnier

Mussot

et al. 2016

Phys. Rev. A

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We study theoretically and numerically the dynamics of a passive optical fiber ring cavity pumped by a highly incoherent wave -an incoherently injected fiber laser. The theoretical analysis reveals that the turbulent dynamics of the cavity is dominated by the Raman effect. The forced-dissipative nature of the fiber cavity is responsible for a large diversity of turbulent behaviors: Besides nonequilibrium statistical stationary states, we report the formation of a periodic pattern of spectral incoherent solitons, or the formation of different types of spectral singularities, e.g., dispersive shock waves and incoherent spectral collapse behaviors. We derive a mean-field kinetic equation that describes in detail the different turbulent regimes of the cavity and whose structure is formally analogous to the weak Langmuir turbulence kinetic equation in the presence of forcing and damping. A quantitative agreement is obtained between the simulations of the nonlinear Schrödinger equation with cavity boundary conditions and those of the mean-field kinetic equation and the corresponding singular integro-differential reduction, without using adjustable parameters. We discuss the possible realization of a fiber cavity experimental set-up in which the theoretical predictions can be observed and studied.

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Strong Langmuir turbulence with and without collapse: experimental study

Cited by 25 publications

References 33 publications

Cavitating Langmuir Turbulence in the Terrestrial Aurora

Cavitating Langmuir Turbulence in the Terrestrial Aurora

Artificial Aurora Experiments and Application to Natural Aurora

Weak Langmuir optical turbulence in a fiber cavity

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