Simulations of auroral plasma processes: Electric fields, waves and particles

Singh, Nagendra; Thiemann, H.; Schunk, R. W.

doi:10.1016/0032-0633(87)90162-0

Cited by 46 publications

(32 citation statements)

References 69 publications

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“…Our simulation discussed here reveals this feature of the density at high altitudes in an auroral potential structure associated with an arc. We have reported similar features in smaller scale simulations [Singh et al, 2005b] and also in very early PIC simulations of V-shaped potential structures [Singh et al, , 1987. The basic physics here is that the hot ions are trapped inside the deepest negative potential, giving the increase in the density as proposed in an early model of the auroral arc by Kan and Akasofu [1979].…”

Section: Potential and Density Structures Of The Moving V-shaped Doubsupporting

confidence: 74%

“…The Geotail observation was explained by numerical simulations of bump-on-the-tail electron beam plasma instabilities [Omura et al, , 1996Miyake et al, 1998]. The connection between double layers and electron holes is known since the very early simulations of double layers [Singh, 1982;Singh and Schunk, 1982a, 1982b, 1984Singh et al, 1987], including the plateauing of the DL-accelerated electron beams by the plasma turbulence mainly consisting of the electron holes Thiemann, 1980a, 1980b]. This connection was eventually confirmed by satellite observations both in the upward and downward current regions [Carlson et al, 1998;Ergun et al, 1998;McFadden et al, 1999].…”

Section: Introductionmentioning

confidence: 90%

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

2011

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[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,

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Section: Potential and Density Structures Of The Moving V-shaped Doubsupporting

confidence: 74%

Section: Introductionmentioning

confidence: 90%

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

2011

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“…Hence a small number of such layers are required only to provide the total "inverted-V" electron energy in bright aurorae. It should be stressed that the observations discussed in the present paper are in good agreement with recent numerical simulation results on generation of holes (Singh et al, 1987;Singh and Khazanov, 2003). In particular, Singh et al (1987) predicted the main features of panel (e) in Fig.…”

Section: Discussionsupporting

confidence: 80%

“…It should be stressed that the observations discussed in the present paper are in good agreement with recent numerical simulation results on generation of holes (Singh et al, 1987;Singh and Khazanov, 2003). In particular, Singh et al (1987) predicted the main features of panel (e) in Fig. 1 from simulations, namely a wide upward current sheet sandwiched between two return current regions.…”

Section: Discussionsupporting

confidence: 79%

Crossing a narrow-in-altitude turbulent auroral acceleration region

Pottelette¹,

Treumann

Georgescu

2004

Nonlin. Processes Geophys.

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Abstract. We report on the in situ identification of a narrow electrostatic acceleration layer (electrostatic shock) containing intense plasma turbulence in the upward current region, and its effect on auroral particles. Wave turbulence recorded in the center of the layer differs in character from that recorded above and beneath. It is concluded that the shock is sustained by different nonlinear waves which, at each level, act on the particles in such a way to produce a net upward directed electric field. The main power is in the ion acoustic range. We point out that anomalous resistivities are incapable of locally generating the observed parallel potential drop.

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“…Such features of the potential structures in the upward current plasma are reported from Polar (Hull et al, 2003); Ergun et al (2004) describe such structures as textbook examples. As a matter of fact such structures were reported from early 2-D simulations of Singh et al (1987) and Winglee et al (1988) in plasmas driven by current sheets. The trajectory T2 in Fig.…”

Section: Parallel and Perpendicular Electric Fields And Density Cavitiesmentioning

confidence: 96%

Dynamical behavior of U-shaped double layers: cavity formation and filamentary structures

Singh

Deverapalli

Rajagiri

et al. 2005

Nonlin. Processes Geophys.

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Abstract.Observations from the Polar and FAST satellites have revealed a host of intriguing features of the auroral accelerations processes in the upward current region (UCR). These features include: (i) large-amplitude parallel (E || ) and perpendicular (E ⊥ ) fluctuating as well as quasi-static electric fields in density cavities, (ii) fairly large-amplitude unipolar parallel electric fields like in a strong double layer (DL), (iii) variety of wave modes, (iv) counter-streaming of upward going ion beams and downward accelerated electrons, (v) horizontally corrugated bottom region of the potential structures (PS), in which electron and ion accelerations occur, (vi) filamentary ion beams in the corrugated PS, and (vii) both upward and downward moving narrow regions of parallel electric fields, inferred from the frequency drifts of the auroral kilometric radiations. Numerical simulations of U-shaped potential structures reveal that such observed features of the UCR are integral parts of dynamically evolving auroral Ushaped potential structures. Using a 2.5-D particle-in-cell (PIC) code we simulate a U-shaped broad potentialstructure (USBPS). The dynamical behavior revealed by the simulation includes: (i) recurring redistribution of the parallel potential drop (PPD) in the PS, (ii) its up and downward motion, (iii) formation of filaments in the potential and density structures, and (iv) creation of filamentary as well as broad extended density cavities. The formation of the filamentary structures is initiated by an ion-beam driven instability of an oblique ion mode trapped inside a broad cavity, when it becomes sufficiently thin in height. The filaments of the PS create filamentary electron beams, which generate waves at frequencies above the lower hybrid frequency, affecting plasma heating. This results in plasma evacuation and formation of a cavity extended in height. The waves associated with filamentary electron beams also evolve into electron holes. The transverse and parallel scale lengths of the regions with large E || and E ⊥ as well as their magnitudes are compared with satellite data.

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Simulations of auroral plasma processes: Electric fields, waves and particles

Cited by 46 publications

References 69 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

Crossing a narrow-in-altitude turbulent auroral acceleration region

Dynamical behavior of U-shaped double layers: cavity formation and filamentary structures

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