Drift-Alfvén fluctuations associated with a narrow pressure striation
نویسندگان
چکیده
formulation is given in terms of the coupling of the fluctuating axial fields (Ẽz ,B̃z) and incorporates shear and compressional Alfvén waves, drift waves, and ion acoustic waves. The kinetic response of the electrons includes pitch-angle scattering ~Lorentz model! and the ions are treated as a magnetized, cold fluid. Detailed quantitative comparisons of the theoretical predictions are made with laboratory observations of fluctuations generated in controlled pressure depletions @J. E. Maggs and G. J. Morales, Phys. Plasmas 4, 290 ~1997!# and in narrow temperature plumes @A. T. Burke, J. E. Maggs, and G. J. Morales, Phys. Rev. Lett. 81, 3659 ~1998!#. © 2000 American Institute of Physics. @S1070-664X~00!01101-0#
منابع مشابه
Fluctuations associated with a filamentary density depletion
Density and magnetic fluctuations arising spontaneously in a narrow field-aligned density striation in a magnetized discharge He plasma are found to exhibit a radial eigenmode structure. The nature of the fluctuations depends upon the electron plasma beta, be . For be greater than the electron to ion mass ratio (be.m/M ) the frequency spectrum exhibits sharply peaked eigenfrequencies with the d...
متن کاملLaboratory studies of field-aligned density striations and their relationship to auroral processes*
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...
متن کاملMutational Pressure Drives Evolution of Synonymous Codon Usage in Genetically Distinct Oenothera plastomes
Background: Most of the amino acids are encoded by more than one codon, termed as synonymous codons. Synonymous codon usage is not random as it is unique to species. In each amino acid family, some synonymous codons are preferred and this is referred to as synonymous codon usage bias (SCUB). Trends associated with evolution of SCUB and factors influencing its diversification in plastomes of gen...
متن کاملExperimental study of fluctuations excited by a narrow temperature filament in a magnetized plasma
A systematic study is made of the spontaneous growth of fluctuations in temperature, density, and magnetic field in a narrow ~on the order of the electron skin depth! field-aligned temperature filament embedded in a large magnetized plasma. Two broad classes of fluctuation ~‘‘low’’ and ‘‘high’’ frequency modes! have been identified and studied in detail. A high-frequency drift-Alfvén mode grows...
متن کاملSecondary instabilities of large scale flow and magnetic field in the electromagnetic short wavelength drift-Alfvén wave turbulence
It is shown that the short wavelength ~k' 2 r i .1, k' is the characteristic wave vector, and r i is the ion Larmor radius! electromagnetic drift wave turbulence in typical conditions is unstable with respect to the excitation of large scale perturbations of the plasma flow and magnetic field. It is found that the generation of zonal flow is reduced ~compared to the long wavelength ion temperat...
متن کامل