Eigenoscillations of the Differentially Rotating Sun: I. 22-year, 4000-year, and quasi-biennial modes

Retrograde waves with frequencies much lower than the rotation frequency become trapped in the solar radiative interior. The eigenfunctions of the compressible, nonadiabatic, Rossby-like modes ($\epsilon$-mechanism and radiative losses taken into account) are obtained by an asymptotic method assuming a very small latitudinal gradient of rotation, without an arbitrary choice of other free parameters. An integral dispersion relation for the complex eigenfrequencies is derived as a solution of the boundary value problem. The discovered resonant cavity modes (called R-modes) are fundamentally different from the known r-modes: their frequencies are functions of the solar interior structure, and the reason for their existence is not related to geometrical effects. The most unstable R-modes are those with periods of 1--3 yr, 18--30 yr, and 1500--20000 yrs; these three separate period ranges are known from solar and geophysical data. The growing times of those modes which are unstable with respect to the $\epsilon$-mechanism are $\approx 10^2, 10^3,$ and $10^5$ years, respectively. The amplitudes of the R-modes are growing towards the center of the Sun. We discuss some prospects to develop the theory of R-modes as a driver of the dynamics in the convective zone which could explain, e.g., observed short-term fluctuations of rotation, a control of the solar magnetic cycle, and abrupt changes of terrestrial climate in the past.Comment: 17 pages, 6 figures, To appear in Astronomy and Astrophysic

Eigenoscillations of the differentially rotating Sun: II. Generalization of Laplace's tidal equation

The general PDE governing linear, adiabatic, nonraradial oscillations in a spherical, differentially and slowly rotating non-magnetic star is derived. This equation describes mainly low-frequency and high-degree g-modes, convective g-modes, and rotational Rossby-like vorticity modes and their mutual interaction for arbitrarily given radial and latitudinal gradients of the rotation rate. In "traditional approximation" the angular parts of the eigenfunctions are described by Laplace's tidal equation generalized here to take into account differential rotation. From a qualitative analysis of Laplace's tidal equation the sufficient condition for the formation of the dynamic shear latitudinal Kelvin-Helmholtz instability (LKHI) is obtained. The exact solutions of Laplace's equation for low frequencies and rigid rotation are obtained. There exists only a retrograde wave spectrum in this ideal case. The modes are subdivided into two branches: fast and slow modes. The long fast waves carry energy opposite to the rotation direction, while the shorter slow-mode group velocity is in the azimuthal plane along the direction of rotation. The eigenfuncions are expressed by Jacobi's polynomials which are polynomials of higher order than the Legendre's for spherical harmonics. The solar 22-year mode spectrum is calculated. It is shown that the slow 22-year modes are concentrated around the equator, while the fast modes are around the poles. The band of latitude where the mode energy is concentrated is narrow, and the spatial place of these band depends on the wave numbers (l, m).Comment: 16 pages, 11 figures, to appear in Astronomy and Astrophysic

Gravitational Instability in Radiation Pressure Dominated Backgrounds

I consider the physics of gravitational instabilities in the presence of dynamically important radiation pressure and gray radiative diffusion, governed by a constant opacity, kappa. For any non-zero radiation diffusion rate on an optically-thick scale, the medium is unstable unless the classical gas-only isothermal Jeans criterion is satisfied. When diffusion is "slow," although the dynamical Jeans instability is stabilized by radiation pressure on scales smaller than the adiabatic Jeans length, on these same spatial scales the medium is unstable to a diffusive mode. In this regime, neglecting gas pressure, the characteristic timescale for growth is independent of spatial scale and given by (3 kappa c_s^2)/(4 pi G c), where c_s is the adiabatic sound speed. This timescale is that required for a fluid parcel to radiate away its thermal energy content at the Eddington limit, the Kelvin-Helmholz timescale for a radiation pressure supported self-gravitating object. In the limit of "rapid" diffusion, radiation does nothing to suppress the Jeans instability and the medium is dynamically unstable unless the gas-only Jeans criterion is satisfied. I connect with treatments of Silk damping in the early universe. I discuss several applications, including photons diffusing in regions of extreme star formation (starburst galaxies & pc-scale AGN disks), and the diffusion of cosmic rays in normal galaxies and galaxy clusters. The former (particularly, starbursts) are "rapidly" diffusing and thus cannot be supported against dynamical instability in the linear regime by radiation pressure alone. The latter are more nearly "slowly" diffusing. I speculate that the turbulence in starbursts may be driven by the dynamical coupling between the radiation field and the self-gravitating gas, perhaps mediated by magnetic fields. (Abridged)Comment: 15 pages; accepted to Ap

Neutrino Oscillations, Fluctuations and Solar Magneto-gravity Waves

This review has two parts. The first part summarizes the current observational constraints on fluctuations in the solar medium deep within the solar Radiative Zone, and shows how the KamLAND and SNO-salt data combine to make the experimental determination of the neutrino oscillation parameters largely insensitive to prior assumptions about the nature of these oscillations. As part of a search for plausible sources of solar fluctuations to which neutrinos could be sensitive, the second part of the talk summarizes a preliminary analysis of the influence of magnetic fields on helioseismic waves. Using simplifying assumptions which should apply to modes in the solar radiative zone, we find a resonance between Alfven waves and helioseismic g-modes which potentially modifies the solar density profile fairly significantly over comparatively short distance scales, too narrow to be ruled out by present-day analyses of p-wave helioseismic spectra.Comment: Plenary talk presented at AHEP 2003, Valencia, Spain, October 200

Large mixing angle oscillations as a probe of the deep solar interior

We re-examine the sensitivity of solar neutrino oscillations to noise in the solar interior using the best current estimates of neutrino properties. Our results show that the measurement of neutrino properties at KamLAND provides new information about fluctuations in the solar environment on scales to which standard helioseismic constraints are largely insensitive. We also show how the determination of neutrino oscillation parameters from a combined fit of KamLAND and solar data depends strongly on the magnitude of solar density fluctuations. We argue that a resonance between helioseismic and Alfven waves might provide a physical mechanism for generating these fluctuations and, if so, neutrino-oscillation measurements could be used to constrain the size of magnetic fields deep within the solar radiative zone.Comment: 13 pages, LaTeX file using AASLaTeX, 6 figures included. Improved version including the new KamLAND data. To appear in APJ letter

Resonant origin for density fluctuations deep within the Sun: helioseismology and magneto-gravity waves

We analyze helioseismic waves near the solar equator in the presence of magnetic fields deep within the solar radiative zone. We find that reasonable magnetic fields can significantly alter the shapes of the wave profiles for helioseismic g-modes. They can do so because the existence of density gradients allows g-modes to resonantly excite Alfven waves, causing mode energy to be funnelled along magnetic field lines, away from the solar equatorial plane. The resulting wave forms show comparatively sharp spikes in the density profile at radii where these resonances take place. We estimate how big these waves might be in the Sun, and perform a first search for observable consequences. We find the density excursions at the resonances to be too narrow to be ruled out by present-day analyses of p-wave helioseismic spectra, even if their amplitudes were to be larger than a few percent. (In contrast it has been shown in (Burgess et al. 2002) that such density excursions could affect solar neutrino fluxes in an important way.) Because solar p-waves are not strongly influenced by radiative-zone magnetic fields, standard analyses of helioseismic data should not be significantly altered. The influence of the magnetic field on the g-mode frequency spectrum could be used to probe sufficiently large radiative-zone magnetic fields should solar g-modes ever be definitively observed. Our results would have stronger implications if overstable solar g-modes should prove to have very large amplitudes, as has sometimes been argued.Comment: 18 pages, 6 figures; misprints correcte

Cornering Solar Radiative-Zone Fluctuations with KamLAND and SNO Salt

We update the best constraints on fluctuations in the solar medium deep within the solar Radiative Zone to include the new SNO-salt solar neutrino measurements. We find that these new measurements are now sufficiently precise that neutrino oscillation parameters can be inferred independently of any assumptions about fluctuation properties. Constraints on fluctuations are also improved, with amplitudes of 5% now excluded at the 99% confidence level for correlation lengths in the range of several hundred km. Because they are sensitive to correlation lengths which are so short, these solar neutrino results are complementary to constraints coming from helioseismology.Comment: 4 pages, LaTeX file using RevTEX4, 6 figures include

БИОЛОГИЧЕСКАЯ ЭФФЕКТИВНОСТЬ РАЗЛИЧНЫХ ПРЕПАРАТОВ ПРОТИВ СЕМЕННОЙ ИНФЕКЦИИ СОСУДИСТОГО БАКТЕРИОЗА КАПУСТЫ

Black rot (pathogen – Xanthomonas campestris pv. campestris) is one of the most harmful diseases of brassicas. Seedlings growing in trays in greenhouse can meet rapid spreading of the pathogen and heavy yield loss even at very low seed infection level. This work was targeted on efficiency comparison for different plant protection agents against black root infection in seeds. Antibacterial effect of the agents was tested in vitro by well diffusion, direct placement of the agent onto bacterial lawn, and by incubation of bacterial suspension with the agents. Biological efficiency of the agents against seed infection was tests by seed soaking or by wet treatment. High antibacterial effect against black rot pathogen in vitro was shown for bacteriophage cocktail, Biocomposite-correct, Zeroxxe, Peroxyacetic acid (NUK15), Ps 11, and Kocide 2000. Highest biological efficiency against seed infection by black rot was shown for bacteriophage cocktail, Biocomposite-correct, Zeroxxe, Peroxyacetic acid (NUK15), and Kocide 2000.Сосудистый бактериоз (возбудитель – Xanthomonas campestris pv. campestris) – одна из наиболее опасных болезней капустных культур. При выращивании рассадным методом даже небольшая зараженность семян приводит к массовому распространению патогена и, в дальнейшем, к значительным потерям урожая в поле. Целью работы было сравнительное испытание эффективности препаратов различного происхождения в отношении семенной инфекции сосудистого бактериоза капусты. Проводили оценку антибактериальной активности препаратов in vitro методом диффузии из лунок, методом нанесения капли препарата на газон бактерий, а также методом совместной инкубации суспензий испытываемых препаратов и патогена. Оценку биологическую эффективности препаратов против семенной инфекции сосудистого бактериоза капусты проводили методами замачивания семян и обработки с увлажнением. Показано, что сильной антибактериальной активностью по отношению к возбудителю сосудистого бактериоза капусты в условиях in vitro обладали консорциум бактериофагов, Биокомпозит-коррект, Зерокс, НУК 15, Ps 11 и Косайд 2000. Наибольшую биологическую эффективность в подавлении семенной инфекции сосудистого бактериоза показали бактериофаги, Биокомпозит-коррект, НУК 15, Зерокс и Косайд 2000