Electron two-stream instability and its application in solar and heliophysics

Che, H.

doi:10.1142/s0217732316300184

Cited by 19 publications

(13 citation statements)

References 105 publications

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“…In Fig. 4D, we show an example of caviton in the xy plane for the Langmuir envelope plotted in red in (20). The electron temperature along the magnetic field Tex inside the caviton is shown in Fig.…”

Section: Simulation Results Of Cyclic Emissionmentioning

confidence: 99%

“…The linear stage only lasts for ωpe,0t = 2 as defined by the growth rate of the ETSI from quasi-linear theory [i.e., γ = √ 3/2(n b0 /nc0) 1/3 ωpe,0 ≈ 2ωpe,0]. During the growth stage, the large beam drift suppresses the generation of Langmuir waves (20). The fastest-growing mode of the solitary wave has kx λDe,0 ≈ vte,0/v bd,0 ≈ 0.1 and ω/ωpe,0 ≈ (n b0 /nc0) 1/3 ωpe,0 ≈ 0.5ωpe,0 as shown in Figs. 2A and 3A.…”

Section: Simulation Results Of Cyclic Emissionmentioning

confidence: 99%

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How electron two-stream instability drives cyclic Langmuir collapse and continuous coherent emission

Che

Goldstein

Diamond

et al. 2017

Proc. Natl. Acad. Sci. U.S.A.

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Continuous plasma coherent emission is maintained by repetitive Langmuir collapse driven by the nonlinear evolution of a strong electron two-stream instability. The Langmuir waves are modulated by solitary waves in the linear stage and electrostatic whistler waves in the nonlinear stage. Modulational instability leads to Langmuir collapse and electron heating that fills in cavitons. The high pressure is released via excitation of a shortwavelength ion acoustic mode that is damped by electrons and reexcites small-scale Langmuir waves; this process closes a feedback loop that maintains the continuous coherent emission.electron beams | nonlinear wave interaction | Langmuir collapse | coherent emission | plasma turbulence E lectron beams accelerated by solar flares and nanoflares are believed to be responsible for several types of solar radio bursts observed in the corona and interplanetary medium, including flare-associated coronal type U and J and interplanetary type III radio bursts, and nanoflare-associated weak coronal type III bursts (1-4). In 1958, Ginzburg and Zhelezniakov first proposed a basic framework for such bursts, which was subsequently refined by others (refs. 5 and 6 and references therein). In essence, the scenario is one in which the electron two-stream instability (ETSI), driven by electron beams, generates Langmuir waves that are converted into plasma coherent emission via nonlinear three-wave coupling [e.g., two Langmuir waves and one ion acoustic wave (IAW)]. However, the mechanism whereby the nonlinear ETSI produces coherent emission with a duration of several orders of magnitude longer than the linear saturation time is not well understood (6-9). Nonlinear evolution of ETSI is a fundamental problem in nonlinear wave theory in which disparate three-wave couplings dominate the energy transport and dissipation (10). It has broad applications in plasma physics, planetary physics, and astrophysics, such as terahertz emission in laser beam experiments, radio bursts from Jupiter, pulsars, and the formation of exotic astrophysical objects.In the classical Kolmogorov turbulence scenario, the balance between energy input and its final absorption is controlled by a nonlinear cascade from large spatial scales (the region of external forcing) to viscosity-dominated short wavelengths. In plasmas, the source of instability is often beams of charged particles that generate Langmuir waves. At shorter wavelengths, the natural candidate to provide the sink of wave energy is Landau damping. However, nonlinear disparate wave interactions, it follows from direct calculation of basic three-wave coupling, can only lead to inverse cascades (to longer wavelengths) through modulational instability (11), and away from the Landau damping region of the spectrum. The eventual nonlinear process capable of overriding this inverse cascade was suggested by Zakharov, namely Langmuir collapse (LC), which is analogous to a selffocusing of the Langmuir waves packets, or cavitons (12, 13). LC has been discovered in both experimen...

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Section: Simulation Results Of Cyclic Emissionmentioning

confidence: 99%

Section: Simulation Results Of Cyclic Emissionmentioning

confidence: 99%

How electron two-stream instability drives cyclic Langmuir collapse and continuous coherent emission

Che

Goldstein

Diamond

et al. 2017

Proc. Natl. Acad. Sci. U.S.A.

Self Cite

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“…In figure 8( c ) ( ) the instability is fully formed. The trapped electrons oscillate inside holes and, as a first approximation, they are governed by the energy conservation (Che 2016). The adiabatic motions of trapped electrons quickly exchange energy between the electrons and waves (Sagdeev & Galeev 1969; Che et al.…”

Section: Code Validationmentioning

confidence: 99%

Enhanced biDimensional pIc: an electrostatic/magnetostatic particle-in-cell code for plasma based systems

Gallina¹,

Magarotto

Manente³

et al. 2019

J. Plasma Phys.

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EDI (enhanced biDimensional pIc) is a two-dimensional (2-D) electrostatic/magnetostatic particle-in-cell (PIC) code designed to optimize plasma based systems. The code is built on an unstructured mesh of triangles, allowing for arbitrary geometries. The PIC core is comprised of a Boris leapfrog scheme that can manage multiple species. Particle tracking locates particles in the mesh, using a fast and simple priority-sorting algorithm. A magnetic field with an arbitrary topology can be imposed to study the magnetized particle dynamics. The electrostatic fields are then computed by solving Poisson’s equation with a a finite element method solver. The latter is an external solver that has been properly modified in order to be integrated into EDI. The major advantage of using an external solver directly incorporated into the EDI structure is its strong flexibility, in fact it is possible to couple together different physical problems (electrostatic, magnetostatic, etc.). EDI is written in C, which allows the rapid development of new modules. A big effort in the development of the code has been made in optimization of the linking efficiency, in order to minimize computational time. Finally, EDI is a multiplatform (Linux, Mac OS X) software.

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“…ETSI is an electrostatic instability and shows different physical evolutions in cold plasma and warm plasma. The details can be found in a recent review [66] and references therein. The plasma is cold if the wave phase speed v p is much larger than the electron thermal speed v te , i.e.…”

Section: Electron Two-stream Instabilitymentioning

confidence: 99%

“…Different from cold plasma, Langmuir waves are produced and Landau damping becomes the dominant process. Let ω = ω r + iγ where γ ω r ∼ ω pe,0 , the dispersion relation can be found as for two beams 1 & 2 [68,66]:…”

Section: Electron Two-stream Instabilitymentioning

confidence: 99%

How Nanoflares Produce Kinetic Waves, Nano-Type III Radio Bursts, and Non-Thermal Electrons in the Solar Wind

Che

2018

J. Phys.: Conf. Ser.

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Observations of the solar corona and the solar wind discover that the solar wind is unsteady and originates from the impulsive events near the surface of the Sun's atmosphere. How solar coronal activities affect the properties of the solar wind is a fundamental issue in heliophysics. We report a simulation and theoretical investigation of how nanoflare accelerated electron beams affect the kinetic-scale properties of the solar wind and generate coherent radio emission. We show that nanoflare-accelerated electron beams can trigger a nonlinear electron two stream instability, which generates kinetic Alfvén and whistler waves, as well as a non-Maxwellian electron velocity distribution function, consistent with observations of the solar wind. The plasma coherent emission produced in our model agrees well with the observations of Type III, J and V solar radio bursts. Open questions in the kinetic solar wind model are also discussed.

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Electron two-stream instability and its application in solar and heliophysics

Cited by 19 publications

References 105 publications

How electron two-stream instability drives cyclic Langmuir collapse and continuous coherent emission

How electron two-stream instability drives cyclic Langmuir collapse and continuous coherent emission

Enhanced biDimensional pIc: an electrostatic/magnetostatic particle-in-cell code for plasma based systems

How Nanoflares Produce Kinetic Waves, Nano-Type III Radio Bursts, and Non-Thermal Electrons in the Solar Wind

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