3-D Magnetohydrodynamics Simulation of the Solar Emerging Flux
Satoshi Nozawa
A series of three-dimensional magnetohydrodynamic simulations are used
to study the nonlinear evolution of the magnetic buoyancy instability
of a magnetic flux sheet with magnetic shear. A horizontal flux sheet
that is initially placed below the solar photosphere is susceptible to
both the interchange instability and the Parker instability. The
growth rate in the linear stage of the instability in the numerical
simulation is consistent with that predicted by the linear theory. In
the nonlinear stage, the development depends on the initial
perturbation as well as the initial magnetic field configuration.
When an initial perturbation is assumed to be periodic, the emerging
flux rises to the corona and the magnetic field expands like a
potential field, as observed in 2D simulations. When an initial
non-periodic perturbation or random perturbations are assumed, the
magnetic flux expands horizontally when the magnetic field emerges a
little into the photosphere. The distribution of the magnetic field
and gas tends to be in a new state of magnetohydrostatic equilibrium.
When magnetic shear is present in the initial magnetic flux sheets,
the interchange mode is stabilized so that the emerging loop is higher
than in the no magnetic shear case.
Correspondence
Satoshi Nozawa (snozawa@env.sci.ibaraki.ac.jp), Ibaraki Univ.
presentation
poster