Neutrino magnetohydrodynamics

Abstract

A new neutrino magnetohydrodynamics (NMHD) model is formulated, where the effects of the charged weak current on the electron-ion magnetohydrodynamic fluid are taken into account. The model incorporates in a systematic way the role of the Fermi neutrino weak force in magnetized plasmas. A fast neutrino-driven short wavelengths instability associated with the magnetosonic wave is derived. Such an instability should play a central role in strongly magnetized plasma as occurs in supernovae, where dense neutrino beams also exist. In addition, in the case of nonlinear or high frequency waves, the neutrino coupling is shown to be responsible for breaking the frozen-in magnetic field lines condition even in infinite conductivity plasmas. Simplified and ideal NMHD assumptions were adopted and analyzed in detail. V

Instabilities and propagation of neutrino magnetohydrodynamic waves in arbitrary direction

“…In [16], for simplicity it was supposed that k · V A = 0, which allows to discard several terms of Eq. (15).…”

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In a previous work [16], a new model was introduced, taking into account the role of the Fermi weak force due to neutrinos coupled to magnetohydrodynamic plasmas. The resulting neutrinomagnetohydrodynamics was investigated in a particular geometry associated with the magnetosonic wave, where the ambient magnetic field and the wavevector are perpendicular.

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Coupling between ion-acoustic waves and neutrino oscillations

“…Also take E 0 = 10 MeV, κ B T e = 100 keV, and the maximal growth rate is γ max = 24.18 s −1 . Therefore, 1/γ max ∼ 0.04 s, which is fast enough to drive a supernova explosion whose accepted characteristic time is around 1 second, as well as of the same order of magnitude of other neutrino-plasma instability growth rates (see [5] for a review, and more recent results in [8]). Figure 1 shows the numerical value of instability growth rate, for different normalized electron-neutrino populations.…”

“…Here, we generalize this work, by taking into account a non-zero neutrino beam coherence and searching for ion-sound wave stability near static equilibria. Contributions from the magnetic field, which were recently considered in the frame of a neutrino-MHD model [8], will be ignored.…”

Collisional effects, ion-acoustic waves, and neutrino oscillations

“…Here a possible avenue for an alternative experimental test of these oscillations is also provided, in terms of collective plasma oscillations. Recently, also the impact of neutrino coupling on MHD waves was established, with a new perspective for joint astrophysical plasma and elementary particles approaches [7]. The radial flux far from the center of the neutrinosphere can be accurately treated as a collimated beam, with small angular spread [4].…”