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Ring-shaped velocity distribution functions in energy-dispersed structures formed at the boundaries of a proton stream injected into a transverse magnetic field: Test-kinetic results

dc.contributor.authorVoitcu, G.
dc.contributor.authorEchim, M.M.
dc.date2012
dc.date.accessioned2016-03-29T10:07:38Z
dc.date.available2016-03-29T10:07:38Z
dc.identifier.urihttps://orfeo.belnet.be/handle/internal/3053
dc.descriptionIn this paper, we discuss the formation of ring-shaped and gyro-phase restricted velocity distribution functions (VDFs) at the edges of a cloud of protons injected into non-uniform distributions of the electromagnetic field. The velocity distribution function is reconstructed using the forward test-kinetic method. We consider two profiles of the electric field: (1) a non-uniform E-field obtained by solving the Laplace equation consistent with the conservation of the electric drift and (2) a constant and uniform E-field. In both cases, the magnetic field is similar to the solutions obtained for tangential discontinuities. The initial velocity distribution function is Liouville mapped along numerically integrated trajectories. The numerical results show the formation of an energy-dispersed structure due to the energy-dependent displacement of protons towards the edges of the cloud by the gradient-B drift. Another direct effect of the gradient-B drift is the formation of ring-shaped velocity distribution functions within the velocity-dispersed structure. Higher energy particles populate the edges of the proton beam, while smaller energies are located in the core. Non-gyrotropic velocity distribution functions form on the front-side and trailing edge of the cloud; this effect is due to remote sensing of energetic particles with guiding centers inside the beam. The kinetic features revealed by the test-kinetic solutions have features similar to in-situ velocity distribution functions observed by Cluster satellites in the magnetotail, close to the neutral sheet.
dc.languageeng
dc.titleRing-shaped velocity distribution functions in energy-dispersed structures formed at the boundaries of a proton stream injected into a transverse magnetic field: Test-kinetic results
dc.typeArticle
dc.subject.frascatiPhysical sciences
dc.audienceScientific
dc.subject.freeE-field
dc.subject.freeElectric drift
dc.subject.freeEnergetic particles
dc.subject.freeEnergy dependent
dc.subject.freeEnergy particles
dc.subject.freeIn-situ
dc.subject.freeInitial velocities
dc.subject.freeKinetic features
dc.subject.freeMagnetotails
dc.subject.freeNeutral sheets
dc.subject.freeNon-uniform distribution
dc.subject.freeNumerical results
dc.subject.freeTangential discontinuities
dc.subject.freeTrailing edges
dc.subject.freeTransverse magnetic field
dc.subject.freeElectric fields
dc.subject.freeElectromagnetic fields
dc.subject.freeKinetic theory of gases
dc.subject.freeKinetics
dc.subject.freeLaplace equation
dc.subject.freeMagnetic fields
dc.subject.freeProtons
dc.subject.freeRemote sensing
dc.subject.freePlasmas
dc.source.titlePhysics of Plasmas
dc.source.volume19
dc.source.issue2
dc.source.page22903
Orfeo.peerreviewedYes
dc.identifier.doi10.1063/1.3686134
dc.identifier.scopus2-s2.0-84857861765


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