A double layer review

Block, L. P.

doi:10.1007/bf00642580

Cited by 340 publications

(193 citation statements)

References 21 publications

Supporting

Mentioning

187

Contrasting

Unclassified

Order By: Relevance

“…Note that V teho and V tico are the thermal velocities of the hot electrons injected from the top and cold ions injected from the bottom boundaries, respectively. Such drifts facilitate DL formation by satisfying Bohm conditions [Block, 1978].…”

Section: Methodsmentioning

confidence: 98%

Mesoscale PIC simulation of double layers and electron holes affecting parallel and transverse accelerations of electrons and ions

2011

View full text Add to dashboard Cite

[1] We study the dynamical behavior of potential structures in the auroral upward current region. The study is based on a large two-dimensional particle-in-cell simulation. A double layer (DL) forms in the auroral potential structure in the counterstreaming expansion of cold and hot plasmas from bottom (ionospheric side) and top (magnetospheric side), respectively. Transversely nonuniform converging perpendicular electric field drives the plasma from the top, generating V-shaped potential structure within the expanding plasmas. The dynamical features include (1) recurring formation of the DL, (2) downward motion of the DL over the distance of thousands of Debye lengths, (3) collapse of the existing double layer after the reformation of a new one near the top in the hot magnetospheric plasma, and (4) generation of electron holes (EHs) on the high-potential side of the DL and their downward propagation over a few thousand of Debye lengths, where they are dissipated. The EHs are associated with broadband plasma waves with spectrum peaked near the lower hybrid frequency. The EH turbulence is temporally modulated by low-frequency plasma waves near the ion cyclotron frequency W i . Electrostatic ion cyclotron waves above W i occur on the low-potential side of the DL. Transverse and parallel acceleration/heating of both electrons and ions are studied. The fast moving electron holes are found effective in transverse heating of the cold ionospheric electrons trapped below the DL. Relevance of our results to satellite observations in the auroral plasma is discussed.Citation: Singh, N., S. Araveti, and E. B. Wells (2011), Mesoscale PIC simulation of double layers and electron holes affecting parallel and transverse accelerations of electrons and ions,

show abstract

Section: Methodsmentioning

confidence: 98%

Mesoscale PIC simulation of double layers and electron holes affecting parallel and transverse accelerations of electrons and ions

2011

View full text Add to dashboard Cite

show abstract

“…Many studies exist about double layers and other abrupt transitions of the electric field, and the reader is referred to reviews and articles by Block (1972Block ( . 1978, Goertz (1979), Carlgvi st (1979) , Levine and Crawford (1979).…”

Section: Similarly V E(s) [Dn E /Ds] + N E (S) [Dv E/ds] = 0 (32)mentioning

confidence: 99%

One‐dimensional models of quasi‐neutral parallel electric fields

Stern

1981

J. Geophys. Res.

View full text Add to dashboard Cite

Abstract:Parallel electric fields can exist in the magnetic mirror geometry of auroral field lines if they conform to the quasineutral equilibrium solutions first suggested by Alfve'n and by Persson. Such solutions may contain double-layer discontinuities, reflecting the disparity between the two sources which contribute to their plasma population--the hot and rarefied magnetosphere, mag netically confined, and the cool dense ionosphere, held down by gravity. This study reviews previous results on quasi-neutral equilibria and on double layers, and then examines the effects on such equilibria due to non-unique solutions, potential barriers and field aligned current flows, using as inputs monoenergetic isotropic distribution functions. Among the conclusions reached: (1) Double layer solutions not involving any net current flow are readily constructed; (2) Such layers may occur naturally and may involve a significant fraction of the total field aligned voltage drop; (3) Non-uniqueness of quasi-neutral solutions must be utilized to determine the position of such layers; (4) The gravitational potential barrier which confronts escaping ions plays an important role and must be taken into account; (5) Outbound field aligned currents are carried primarily by precipitating electrons and only a very small fraction of them is due to ionospheric positive ions; (6) Inbound field aligned currents require an appreciable voltage to drive them, and their density is no greater than that of outbound currents; (7) Precipitation with no net J" sets up a "thermoelectric potential" similar to the one predicted by Hultqvist. Overall, the model suggests that quasi-neutral equilibria can explain many of the observed features of field aligned currents and of their associated electric fields, though solutions at this stage do not extend to voltages exceeding 2.2 kV.

show abstract

“…A double layer (DL) is a nonlinear electrostatic electric field localized within two adjacent layers of equal and opposite net charge (Block 1978;Raadu & Rasmussen 1988;Singh et al 1987). It is highly localized to ∼10 λ De because quasineutrality in a plasma can only be violated on λ De scales.…”

Section: Introductionmentioning

confidence: 99%

Suppression of Energetic Electron Transport in Flares by Double Layers

Drake

Swisdak

2012

ApJ

View full text Add to dashboard Cite

During flares and coronal mass ejections, energetic electrons from coronal sources typically have very long lifetimes compared to the transit times across the systems, suggesting confinement in the source region. Particlein-cell simulations are carried out to explore the mechanisms of energetic electron transport from the corona to the chromosphere and possible confinement. We set up an initial system of pre-accelerated hot electrons in contact with ambient cold electrons along the local magnetic field and let it evolve over time. Suppression of transport by a nonlinear, highly localized electrostatic electric field (in the form of a double layer) is observed after a short phase of free-streaming by hot electrons. The double layer (DL) emerges at the contact of the two electron populations. It is driven by an ion-electron streaming instability due to the drift of the back-streaming return current electrons interacting with the ions. The DL grows over time and supports a significant drop in temperature and hence reduces heat flux between the two regions that is sustained for the duration of the simulation. This study shows that transport suppression begins when the energetic electrons start to propagate away from a coronal acceleration site. It also implies confinement of energetic electrons with kinetic energies less than the electrostatic energy of the DL for the DL lifetime, which is much longer than the electron transit time through the source region.

show abstract

A double layer review

Cited by 340 publications

References 21 publications

Mesoscale PIC simulation of double layers and electron holes affecting parallel and transverse accelerations of electrons and ions

Mesoscale PIC simulation of double layers and electron holes affecting parallel and transverse accelerations of electrons and ions

One‐dimensional models of quasi‐neutral parallel electric fields

Suppression of Energetic Electron Transport in Flares by Double Layers

Contact Info

Product

Resources

About