At a horizontally homogeneous isothermal atmosphere approximation, we derive an ordinary six-order differential equation describing linear disturbances with consideration for heat conductivity and viscosity of medium. The wave problem may be solved a
nalytically by representing the solution through generalized hypergeometric functions only at a nonviscous heat-conducting isothermal atmosphere approximation. The analytical solution may be used to qualitatively analyze propagation of acoustic and internal gravity waves (AGWs) in the real atmosphere: a) to classify waves of different frequencies and horizontal scales according to a degree of attenuation and thus according to their ability to appear in observations and in general dynamics of the upper atmosphere; b) to describe variations in amplitude and phase characteristics of disturbances propagating in a height region with dominant dissipation; c) to analyze applicability of quasi-classical wave description to a medium with exponentially growing dissipation. In this paper, we also present wave and quasi-classical methods for deriving waveguide solutions (dissipative ones corresponding to a range of internal gravity waves (IGWs)) with consideration of wave leakage into the upper atmosphere. We propose a qualitative scheme which formally connects the wave leakage solution to the wave solution in the upper dissipative atmosphere. Spatial and frequency characteristics of dissipative disturbances generated by a waveguide leakage effect in the upper atmosphere are demonstrated to agree well with observed characteristics of middle-scale traveling ionospheric disturbances (TIDs).
The paper presents the possibility of fast and quality azimuth disambiguation of vector magnetogram data regardless of location on the solar disc. The new Super Fast and Quality (SFQ) code of disambiguation is tried out on well-known models of Metcal
f et al. (2006), Leka et al. (2009) and artificial model of fixed configuration AR 10930 (Rudenko et al., 2010). We make comparison of Hinode SOT SP vector magnetograms of AR 10930 disambiguated with three codes: SFQ, NPFC (Georgoulis, 2005), and SME (Rudenko et al., 2010). We exemplify the SFQ disambiguation of SDO/HMI measurements of the full disc. The preliminary examination indicates that the SFQ algorithm provides better quality than NPFC and is comparable to SME. In contrast to other codes, SFQ supports relatively high quality of results regardless of the magnetogram proximity to the limb (when being very close to the limb, it is efficient unlike all other algorithms).
An algorithm for calculating three gauge-invariant helicities (self-, mutual- and Berger relative helicity) for a magnetic field specified in a rectangular box is described. The algorithm is tested on a well-known force-free model (Low and Lou, 1990) presented in vector-potential form.
Possibilities in principle for satisfactory removal of the 180-azimuthal ambiguity in the transverse field of vector magnetograms and the extrapolation of magnetic fields independently of their position on the solar disk are shown. Revealed here is a
n exact correspondence between the estimated field and the nonpotential loop structure on the limb. The Metropoliss algorithm modified to work in spherical geometry is used to resolve the azimuthal ambiguity. Based on a version of the optimization method from Rudenko and Myshyakov (2009), we use corrected magnetograms as boundary conditions for magnetic field extrapolation in the nonlinear force-free approximation.
