123 research outputs found
On the physics of waves in the solar atmosphere: Wave heating and wind acceleration
In the area of solar physics, new calculations of the acoustic wave energy fluxes generated in the solar convective zone was performed. The original theory developed was corrected by including a new frequency factor describing temporal variations of the turbulent energy spectrum. We have modified the original Stein code by including this new frequency factor, and tested the code extensively. Another possible source of the mechanical energy generated in the solar convective zone is the excitation of magnetic flux tube waves which can carry energy along the tubes far away from the region. The problem as to how efficiently those waves are generated in the Sun was recently solved. The propagation of nonlinear magnetic tube waves in the solar atmosphere was calculated, and mode coupling, shock formation, and heating of the local medium was studied. The wave trapping problems and evaluation of critical frequencies for wave reflection in the solar atmosphere was studied. It was shown that the role played by Alfven waves in the wind accelerations and the coronal hole heating is dominant. Presently, we are performing calculations of wave energy fluxes generated in late-type dwarf stars and studying physical processes responsible for the heating of stellar chromospheres and coronae. In the area of physics of waves, a new analytical approach for studying linear Alfven waves in smoothly nonuniform media was recently developed. This approach is presently being extended to study the propagation of linear and nonlinear magnetohydrodynamic (MHD) waves in stratified, nonisothermal and solar atmosphere. The Lighthill theory of sound generation to nonisothermal media (with a special temperature distribution) was extended. Energy cascade by nonlinear MHD waves and possible chaos driven by these waves are presently considered
MHD bending waves in a current sheet
Transverse MHD bending waves are considered in an isothermal and compressible two-dimensional current sheet of finite thickness in which the magnetic field changes direction and strength. The general form of the wave equation is obtained. It is shown that rotation of the magnetic field across the current sheet prevents the existence of singular points so that continuous spectrum solutions and the concomitant wave decay disappear. Instead, normal modes exist and closed integral solution for arbitrary current sheet structure are found. The results are discussed in terms of small-scale waves on the heliospheric current sheet
New Fundamental Equation for Classical Waves and its Physical Applications
The irreducible representations of the extended Galilean group are used to
derive the symmetric and asymmetric, in time and space derivatives, wave
equations. It is shown that among these equations only a new asymmetric wave
equation is fundamental. By being fundamental the equation gives the most
complete description of propagating waves as it accounts for the Doppler
effect, forward and backward waves, and makes the wave speed to be the same in
all inertial frames. To demonstrate these properties, the equation is applied
to acoustic waves propagation in an isothermal atmosphere. The derived
fundamental wave equation plays the same role for classical waves as Newton's
law of inertia plays for classical particles
Atomic Model of Dark Matter Halo and Its Quantum Structure
A quantum theory of dark matter particles in a spherical halo is developed by
using the new asymmetric equation, which appeared in [2021, Int. J. Mod. Phys.
A, 36, 2150042]. The theory predicts that each dark matter halo has its core
and envelope, which have very distinct physical properties. The core is free of
any quantum structure and its dark matter particles are in random motion and
frequently collide with each other. However, the envelope has a global quantum
structure that contains quantized orbits populated by the particles. The
predicted quantum structure of the halo resembles an atom, hence, it is here
named the atomic model of dark matter halo. Applications of the theory to a
dark matter halo with a given density profile are described, and predictions of
the theory are discussed
A New Look at the Quantum Measurement Problem
A novel solution to the measurement problem in quantum mechanics is proposed
by using a new asymmetric equation, which is complementary to the Schr\"odinger
equation. Since the latter describes evolution of the wavefunction, it is
demonstrated that the new equation naturally describes collapse of the
wavefunction. This implies that the full representation of the wavefunction in
nonrelativistic quantum mechanics requires both equations
Global and local cutoff frequencies for transverse waves propagating along solar magnetic flux tubes
The propagation of linear transverse waves along a thin isothermal magnetic
flux tube is affected by a global cutoff frequency that separates propagating
and non-propagating waves. In this paper, wave propagation along a thin but
non-isothermal flux tube is considered and a local cutoff frequency is derived.
The effects of different temperature profiles on this local cutoff frequency
are studied by considering different power-law temperature distributions as
well as the semi-empirical VAL C model of the solar atmosphere. The results
show that the conditions for wave propagation strongly depend on the
temperature gradients. Moreover, the local cutoff frequency calculated for the
VAL C model gives constraints on the range of wave frequencies that are
propagating in different parts of the solar atmosphere. These theoretically
predicted constraints are compared to observational data and are used to
discuss the role played by transverse tube waves in the atmospheric heating and
dynamics, and in the excitation of solar atmospheric oscillations.Comment: To be publishd in ApJ Vol. 763. 10 pages, 3 Postscript figure
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