4,956 research outputs found
Characteristics of Quantum Magnetosonic-Wave Dispersion
Using the quantum magnetohydrodynamics (QMHD) model, linear dispersion of
magnetosonic waves are studied in a quasineutral quantum electron-ion plasma in
two distinct regimes of nonrelativistic and relativistic degeneracies
considering also the plasma composition effect. It is shown that the
paramagnetic spin effects of the degenerated electrons plays a key role in
dynamics of magnetosonic waves. The linear wave-speed is found to have minimum
value at some degeneracy parameter in such plasmas. This is due to delicate
interplay between relativistic degeneracy and the Pauli spin-magnetization. It
is also revealed that the plasma composition has significant effect on the
linear dispersion in the relativistic degeneracy limit contrary to that of
nonrelativistic case and Zeeman energy has significant effect in
nonrelativistic degeneracy regime unlike that of relativistic one in the linear
perturbation-limit. Current findings can have important applications in both
inertial plasma confinement and astrophysical degenerate plasmas.Comment: To appear in IEEE Trans. Plasma Sci. arXiv admin note: text overlap
with arXiv:1106.022
Spin-induced localized density excitations in quantum plasmas
In this paper the dominant effect of electron inertia on the dynamics of
localized density excitations is studied in a quantum plasma in the presence of
electron spin effects. Using the quantum magnetohydrodynamics (QMHD) model
including electron tunneling and spin polarization phenomena, it is revealed
that the quantum effects such as plasma paramagnetism and diamagnetism play
inevitable role on soliton existence criteria in quantum plasmas. Furthermore,
it is shown that the magnetosonic localized density-excitation stability
depends strongly on the quantum system dimensionality. Two distinct region of
soliton stability is shown to exist depending on the value of the electron
effective mass, where, the soliton amplitude variation with respect to the
external magnetic field strength is quite opposite in these regions. Current
findings can be important in the study of dynamical nonlinear wave features in
dense laboratory or inertial-confined plasmas.Comment: Paper accepted in journal IEEE Trans. Plasma Sc
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