Dynamics of magnetosphere‐ionosphere coupling including turbulent transport

Lysak, R. L.; Dum, C. T.

doi:10.1029/ja088ia01p00365

Cited by 299 publications

(220 citation statements)

References 59 publications

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“…Streltsov et al [2002] studied this problem with twodimensional fluid simulations including a current-dependent anomalous resistivity term associated with electrostatic ion cyclotron turbulence [Lysak and Dum, 1983]. In this work, the dominant parallel electric field came at low altitudes (∼2 R E geocentric) where the anomalous resistivity maximizes.…”

Section: Discussionmentioning

confidence: 99%

Development of parallel electric fields at the plasma sheet boundary layer

Lysak

Song

2011

J. Geophys. Res.

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[1] Many measurements of auroral particles, in particular recent measurements from the FAST satellite, indicate that the auroral electron distribution is often broad in energy and field-aligned in pitch angle. Such electrons are seen in conjunction with strong kinetic Alfvén waves with small perpendicular wavelength, and so the aurora produced by these electrons has been termed the "Alfvénic aurora." The Alfvénic aurora is predominant at the polar cap boundary of the aurora as well as in the auroral arc that brightens during substorm onset. The process of forming parallel electric fields in Alfvén waves has been investigated by means of three-dimensional two-fluid simulations. Waves with small perpendicular wavelengths can be produced by phase mixing when perpendicular gradients are present in the plasma. At lower altitudes, Alfvén waves can interact with the ionospheric Alfvén resonator and phase mix to scales of a few kilometers. At higher altitudes, the electron thermal speed becomes comparable or larger than the Alfvén speed, and parallel electric fields due to the Landau resonance can develop. This has been modeled in the fluid code by an approximation to the plasma dispersion function used in kinetic theory. Phase mixing is most effective when there are strong gradients, such as at the plasma sheet boundary layer. Simulations indicate that these processes can produce parallel electric fields on scales of a few kilometers (in the cold plasma case) to a few tens of kilometers (in the warm plasma case), comparable to the scale sizes of auroral arcs.

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Section: Discussionmentioning

confidence: 99%

Development of parallel electric fields at the plasma sheet boundary layer

Lysak

Song

2011

J. Geophys. Res.

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“…All sophistications of the microphysics are suppressed. The effect of electrostatic ion-cyclotron waves may be taken into account by a second contribution to v* which is a fraction (~0.2) of the ion gyrofrequency (Lysak & Dum 1983). An application of equations (24) and (25) is the estimate of the macroscopic magnetic diffusivity, D m , related to such a distributed resistivity:…”

Section: Microphysicsmentioning

confidence: 99%

“…This theory has been found to be quite successful in explaining many features of the primary auroral particle distributions. A second class of theories attributes the existence of parallel electric fields to the appearance of anomalous resistivity in intense field-aligned currents (Haerendel 1980;Lysak & Dum 1983). Field-aligned currents play the key role in both theories, but they differ in that the first one depends on hot magnetospheric electrons being the current carriers, whereas the second one deals with the currents as they are continued in the "cold" plasma of the topside ionosphere.…”

Section: Introductionmentioning

confidence: 99%

Acceleration from Field-Aligned Potential Drops

Haerendel

1994

International Astronomical Union Colloquium

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Unstable field-aligned currents are seen as the origin of field-aligned potential drops. They convert energy stored in magnetic shear stresses into kinetic energy. A good fraction of this energy is carried by runaway electrons and ions out of the acceleration region. The paper emphasizes the analogy with mechanical fractures. Simple expressions for the energy conversion rate and the parallel potential drop are derived, the two being linked by the critical current density needed for instability. The origin of the currents (generator) lies mostly in a region remote from that of energy conversion (fracture zone). The transmission of shear stresses and energy from the generator plasma, where the primary forces are applied to the fracture zone is also considered. A closed set of relations allows quantitative evaluation of the energetic particle production efficiency. The decoupling of the plasma on either side of the fracture zone which allows fast stress relief is described in detail, as well as a stationary model for the Alfven wave interaction between fracture zone and generator plasma. A simple concept of the nature of the anomalous resistivity generated by the unstable current leads to an expression for the magnetic diffusivity inside the fracture zone and an estimate of the latter's extent parallel to the magnetic field, whereas its width and length transverse to B follow from the macroscopic relations. Finally and as an example, the theory is applied to the problem of fast electron (and ion) acceleration well above 1 MeV seen to occur in many solar flares. It is obvious that this process belongs to the most powerful production processes of high-energy particles in stellar magnetic fields.

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“…Finally, the global distribution of electric currents reflects the structure of magnetospheric fields as well as the ionospheric plasma state (inhomogeneity of the transverse ionospheric conductivity, peculiarities in neutral atmosphere motion, etc.) (Chmyrev et al, 1988;Feldstein and Galperin, 1985;Heelis, 1988;Heppner, 1972;Lysak and Carlson, 1981;Lysak and Dum, 1983;Titova et al, 1984). Experimental investigation of these phenomena requires the measurement of currents and electric and magnetic fields in the high latitude ionosphere what is the major goal of the VARIANT mission.…”

Section: Scientific Goals Of Variant Projectmentioning

confidence: 99%

“…(Chmyrev et al, 1988;Heelis, 1988;Lysak and Carlson, 1982;Lysak and Dum, 1983;Titova et al, 1984), still there are many unanswered questions in the problem of ionospheremagnetosphere coupling. Namely, one can mention the following :…”

Section: Introductionmentioning

confidence: 99%

Project VARIANT: Current and field measurements on board SICH-1M satellite

Korepanov¹,

Negoda²,

Lizunov³

et al. 2000

Advances in Space Research

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VARIANT is a joint international space experiment on current density measurements in ionosphericmagnetospheric plasmas. The experiment will be performed onboard the Ukrainian remote sensing satellite SICH-1M, that will be launched in 2000 at the polar circular orbit with the inclination of around 83 ° and altitude 670±30 km. The scientific payload includes three instruments for registration of space current density: a split Langmuir probe, a Rogovski coil and a Faraday cup. The first two of these instruments are dedicated to measure current density variations and the last the particles' fluxes. The equipment also includes sensors for measurements of the electric and magnetic field fluctuations in the frequency range from 0

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Dynamics of magnetosphere‐ionosphere coupling including turbulent transport

Cited by 299 publications

References 59 publications

Development of parallel electric fields at the plasma sheet boundary layer

Development of parallel electric fields at the plasma sheet boundary layer

Acceleration from Field-Aligned Potential Drops

Project VARIANT: Current and field measurements on board SICH-1M satellite

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