Article

# Field-Induced Degeneracy Regimes in Quantum Plasmas

Physics of Plasmas (Impact Factor: 2.14). 01/2012; 19(3). DOI: 10.1063/1.3690090

Source: arXiv

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M. Akbari-Moghanjoughi, Feb 22, 2014 Available from: Data provided are for informational purposes only. Although carefully collected, accuracy cannot be guaranteed. The impact factor represents a rough estimation of the journal's impact factor and does not reflect the actual current impact factor. Publisher conditions are provided by RoMEO. Differing provisions from the publisher's actual policy or licence agreement may be applicable.

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**ABSTRACT:**In this paper, using both quantum magnetohydrodynamic (MHD) and magnetohydrostatic (MHS) models of a relativistically degenerate magnetic compact star, the fundamental role of Landau orbital ferromagnetism (LOFER) on the magneto-gravitational stability of such star is revealed. It is shown that the previously suggested magnetic equation of state for LOFER with some generalization of form $B=\beta \rho^{2s/3}$ only within the range $0\leq s\leq 1$ and $0\leq \beta< \sqrt{2\pi}$ leads to magneto-gravitational stability with distinct critical value $\beta_{cr}=\sqrt{2\pi}$ governing the magnetohydrostatic stability of the compact star. Furthermore, the value of the parameters $s$ and $\beta$ is shown to fundamentally control both the quantum and Chandrasekhar gravitational collapse mechanisms and the previously discovered mass-limit on white dwarfs. Current findings can help to understand the origin of magnetism and its inevitable role on the stability of the relativistically degenerate super-dense magnetized matter encountered in many white-dwarfs and neutron stars.Physics of Plasmas 01/2012; 19(5). DOI:10.1063/1.4714611 · 2.14 Impact Factor - [Show abstract] [Hide abstract]

**ABSTRACT:**In this work we study the propagations of normal frequency modes for quantum hydrodynamic (QHD) waves in the linear limit and introduce a new kind of instability in a double-degenerate plasma. Three different regimes, namely, low, intermediate and high magnetic field strengths are considered which span the applicability of the work to a wide variety of environments. Distinct behavior is observed for different regimes, for instance, in the laboratory-scale field regime no frequency-mode instability occurs unlike those of intermediate and high magnetic-field strength regimes. It is also found that the instability of this kind is due to the heavy-fermions which appear below a critical effective-mass parameter ($\mu_{cr}=\sqrt{3}$) and that the responses of the two (lower and upper frequency) modes to fractional effective-mass change in different effective-mass parameter ranges (below and above the critical value) are quite opposite to each other. It is shown that, the heavy-fermion instability due to extremely high magnetic field such as that encountered for a neutron-star crust can lead to confinement of stable propagations in both lower and upper frequency modes to the magnetic poles. Current study can have important implications for linear wave dynamics in both laboratory and astrophysical environments possessing high magnetic fields.Physics of Plasmas 05/2012; 19(7). DOI:10.1063/1.4731726 · 2.14 Impact Factor