Spontaneous Thermal Waves in a Magnetized Plasma

Pace, D. C.; Shi, Meixuan; Maggs, J. E.; Morales, G. J.; Carter, Troy

doi:10.1103/physrevlett.101.035003

Cited by 21 publications

(28 citation statements)

References 18 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…We have 2 1 and the necessary condition for a trigonometric solution for |ξ | W gives γ < √ 1 + /2, so is real in (A1). To have exponentially decreasing solutions for |ξ | > W we require γ > √ 1 − /2, giving real in (A1).…”

Section: Appendix A: Simplified Model For T E (X)mentioning

confidence: 99%

“…To have exponentially decreasing solutions for |ξ | > W we require γ > √ 1 − /2, giving real in (A1). We also have the possibility for free mode solutions for 2 1. The existence of these imply oscillatory solutions for at ξ → ±∞ giving γ < √ 1 − /2.…”

Section: Appendix A: Simplified Model For T E (X)mentioning

confidence: 99%

“…The ion temperature is homogeneous, but the electron temperature T e varies in the direction perpendicular to an externally imposed homogeneous magnetic field, so T e is locally enhanced in a magnetic flux tube. Conditions like these occur often in nature for plasmas out of equilibrium [1] and can also be produced in laboratory plasmas [2]. Wave propagation in such conditions has been studied experimentally [3] and numerically [4].…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Weakly nonlinear ion waves in striated electron temperatures

Guio¹,

Pécseli²

2016

Phys. Rev. E

View full text Add to dashboard Cite

The existence of low-frequency waveguide modes of electrostatic ion acoustic waves is demonstrated in magnetized plasmas for cases where the electron temperature is striated along magnetic field lines. For low frequencies, the temperature striation acts as waveguide that supports a trapped mode. For conditions where the ion cyclotron frequency is below the ion plasma frequency we find a dispersion relation having also a radiative frequency band, where waves can escape from the striation. Arguments for the formation and propagation of an equivalent of electrostatic shocks are presented and demonstrated numerically for these conditions. The shock represents here a balance between an external energy input maintained by ion injection and a dissipation mechanism in the form of energy leakage of the harmonics generated by nonlinear wave steepening. This is a reversible form for energy loss that can replace the time-irreversible losses in a standard Burgers equation.

show abstract

Section: Appendix A: Simplified Model For T E (X)mentioning

confidence: 99%

Section: Appendix A: Simplified Model For T E (X)mentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Weakly nonlinear ion waves in striated electron temperatures

Guio¹,

Pécseli²

2016

Phys. Rev. E

View full text Add to dashboard Cite

show abstract

“…The entropy and complexity are calculated for a time length spanning several rotation periods of the ropes; therefore temporal/spatial smearing is anticipated. High complexities around the flux ropes close to the source (where the rotation and smearing is negligible) could indicate that the chaotic signatures are due to gradient driven modes as in [44,45]. The C-H diagrams display entropy as well as complexity and entropy is absent from figure 12.…”

Section: Complexity and Entropy-flux Ropesmentioning

confidence: 99%

“…In the case of the filament the spectra is exponential, showing a linear relation when plotted on a log(f (w)) − linear(w) plot. It was shown [45], that the presence of Lorentzian pulses in the time series data are responsible for the exponential spectrum. In this work this methodology is extended to volumetric data on magnetic flux ropes.…”

Section: Complexity and Entropy-introductionmentioning

confidence: 99%

Chaos in magnetic flux ropes

Gekelman

Compernolle

DeHaas

et al. 2014

Plasma Phys. Control. Fusion

View full text Add to dashboard Cite

Magnetic flux ropes immersed in a uniform magnetoplasma are observed to twist about themselves, writhe about each other and rotate about a central axis. They are kink unstable and smash into one another as they move. Each collision results in magnetic field line reconnection and the generation of a quasi-separatrix layer. Three-dimensional magnetic field lines are computed by conditionally averaging the data using correlation techniques. Conditional averaging is possible for only a number of rotation cycles as the field line motion becomes chaotic. The permutation entropy can be calculated from the time series of the magnetic field data (this is also done with flows) and is used to calculate the positions of the data on a Jensen-Shannon complexity map. The location of data on this map indicates if the magnetic fields are stochastic, or fall into regions of minimal or maximal complexity. The complexity is a function of space and time. The Lyapunov and Hurst exponents are calculated and the complexity and permutation entropy of the flows and field components are shown throughout the volume.

show abstract

Drift-Alfvén fluctuations and transport in multiple interacting magnetized electron temperature filaments

et al. 2019

View full text Add to dashboard Cite

The results of a basic electron heat transport experiment using multiple localized heat sources in close proximity and embedded in a large magnetized plasma are presented. The set-up consists of three biased probe-mounted crystal cathodes, arranged in a triangular spatial pattern, that inject low energy electrons along a strong magnetic field into a pre-existing, cold afterglow plasma, forming electron temperature filaments. When the three sources are activated and placed within a few collisionless electron skin depths of each other, a non-azimuthally symmetric wave pattern emerges due to interference of the drift-Alfvén modes that form on each filament’s temperature gradient. Enhanced cross-field transport from chaotic ( $\boldsymbol{E}\times \boldsymbol{B}$ , where $\boldsymbol{E}$ is the electric field and $\boldsymbol{B}$ the magnetic field) mixing rapidly relaxes the gradients in the inner triangular region of the filaments and leads to growth of a global nonlinear drift-Alfvén mode that is driven by the thermal gradient in the outer region of the triangle. Azimuthal flow shear arising from the emissive cathode sources modifies the linear eigenmode stability and convective pattern. A steady-current model with emissive sheath boundary predicts the plasma potential and shear flow contribution from the sources.

show abstract

Spontaneous Thermal Waves in a Magnetized Plasma

Cited by 21 publications

References 18 publications

Weakly nonlinear ion waves in striated electron temperatures

Weakly nonlinear ion waves in striated electron temperatures

Chaos in magnetic flux ropes

Drift-Alfvén fluctuations and transport in multiple interacting magnetized electron temperature filaments

Contact Info

Product

Resources

About