نتایج جستجو برای: electron plasma waves

تعداد نتایج: 747494  

2002
Sarah L. McGregor

The effects of collective neutrino-plasma interactions on the linear wave spectrum supported by a magnetized electron-positron plasma in the presence of a neutrino-antineutrino medium are investigated. When a pair-symmetric background neutrino-plasma medium is perturbed by space-charge waves (electrostatic waves associated with electron-positron charge separation), our analysis shows that the n...

Journal: :فیزیک زمین و فضا 0
علیرضا محمودیان institute of geophysics, university of tehran alireza mohebalhojeh institute of geophysics, university of tehran مجید مزرعه فراهانی institute of geophysics, university of tehran wayne scales the bradley department of electrical and computer engineering,virginia tech, usa

on the source of plasma density and electric field perturbations in pmse and pmwe regionspolar mesospheric summer/winter echoes (pmse/pmwe) are very strong radar echoes produced by ionospheric electron density fluctuations at half the radar wavelength. the main focus of this paper is the altitude range 80 to 90 km in summer and altitude range 65-86 km in winter in the polar mesosphere . this pa...

2007
R. Rankin C. E. J. Watt J. C. Samson

[1] Using 1D Vlasov drift-kinetic computer simulations, it is shown that electron trapping in long period standing shear Alfvén waves (SAWs) provides an efficient energy sink for wave energy that is much more effective than Landau damping. It is also suggested that the plasma environment of low altitude auroral-zone geomagnetic field lines is more suited to electron acceleration by inertial or ...

1997
Walter Gekelman Stephen Vincena David Leneman James Maggs

AlfvŽn waves are ubiquitous in space plasmas and are the means by which information about changing currents and magnetic fields are communicated. Shear AlfvŽn waves radiated from sources with cross field scale size on the order of the electron inertial length, δ = c/ωpe, have properties which differ considerably from planar Magneto-hydrodynamic waves. Currents of cross field size , δ, are commo...

1997
J. E. Maggs G. J. Morales

Magnetic field-aligned structures in current, density, and temperature are common features of the auroral ionospheric plasma. These structures both generate and transform low frequency waves in the plasma. The results of laboratory studies of two processes involving magnetic field-aligned density depletions ~striations! that play a role in auroral plasma dynamics are presented. The first proces...

2004
Siming Liu

Stochastic acceleration of electrons and protons by waves propagating parallel to the large scale magnetic field of magnetized plasmas are studied with emphasis on the feasibility of accelerating particles from a thermal background to relativistic energies and with the aim of determining the relative acceleration of the two species in one source. A general result of this investigation is that s...

Journal: :international journal of nano dimension 0
a. elsagh faculty of chemistry, department of chemistry, north tehran branch, islamic azad university, iran. m. tahernejad nuclear science and technology research institute, atomic energy organization of iran.

in recent years, using sol-gel procedure for the purpose of laboratory and industrial synthesis of nano-structures, and especially silica nano-particles, has been significantly increased. in this research, silica particles were synthesized by sol-gel procedure and their physical and chemical properties were studied by means of scanning electron microscopy (sem), transmission electron microscopy...

Journal: :Physical review letters 2006
R S Fletcher X L Zhang S L Rolston

Applying a radio-frequency electric field to an expanding ultracold neutral plasma leads to the observation of as many as six peaks in the emission of electrons from the plasma. These are identified as collective modes of the plasma and are in qualitative agreement with a model of Tonks-Dattner resonances, electron sound waves propagating in a finite-sized, inhomogeneous plasma. Such modes may ...

2013
Volodymyr O. Girka Igor O. Girka Alexander V. Kostenko Ivan V. Pavlenko

Azimuthal Surface Waves (ASWs) are electromagnetic waves of the surface type, which propagate across an external steady magnetic field in plasma filled metal waveguides. The interaction between extraordinary ASWs and an electron beam that rotates along Larmor orbits in the gap between the plasma column and the metal wall is studied here. The initial stage of the ASW excitation is studied analyt...

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