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1.
Using the Baranger-Mozer method, we explore the possibility of diagnosing the flare plasma of forbidden Hei lines, that permits the determination of the plasma oscillation frequency and noise level. Examination of the Hei lines observed in solar flare has led us to conclude that:
  1. the appearance of satellites of forbidden components in the flares spectrum, due to turbulent electric fields, is the most probable for Hei 3819.606 Å lines;
  2. the Baranger-Mozer method is more sensitive to the high-frequency component of turbulent fields than to the low-frequency ones;
  3. the upper limit of the turbulent oscillation level in flares is evaluated.
In the spectrum of the solar flare of 26 September, 1963 we detected satellites of the forbidden component of the 3820 Å line and used its relative intensity to derive the level of low-frequency oscillations (～1.5 kVcm-1).  相似文献   

2.
New computations of massive stars follow the evolution up to advanced stages and include:
  • -A large and flexible nuclear network consisting of 174 nuclear species that are linked by 1742 nuclear reactions.
  • -Semiconvection, overshooting and mass loss.
  • -Modern rates for both strong and weak interaction processes as well as the latest rates for the neutrino processes.
  • -Improved grid distribution and a large number of grid points.
    • The nuclear network and the diffusion equation are solved for each time step during the whole evolution. In this way the accuracy of nuclear yields and chemical abundances are mainly limited by uncertainties in the diffusion coefficient found from the convection theories. Several instability mechanisms may affect the mass loss rates of massive stars and thereby the structure and abundances of WR stars. Due to heavy mass loss at the LBV and WR stages, the masses at the pre-SN stage may be less than 5M ⊙. Yields and abundances throughout the stars are discussed together with the amount of all elements expelled.  相似文献   

    3.
    1. The exotic system H 3 ++ (which does not exist without magnetic field) exists in strong magnetic fields:
      1. In triangular configuration for B≈108–1011?G (under specific external conditions)
      2. In linear configuration for B>1010?G
    2. In the linear configuration the positive z-parity states 1σ g , 1π u , 1δ g are bound states
    3. In the linear configuration the negative z-parity states 1σ u , 1π g , 1δ u are repulsive states
    4. The H 3 ++ molecular ion is the most bound one-electron system made from protons at B>3×1013?G
    Possible application: The H 3 ++ molecular ion may appear as a component of a neutron star atmosphere under a strong surface magnetic field B=1012–1013?G.  相似文献   

    4.
    The properties of small (< 2″) moving magnetic features near certain sunspots are studied with several time series of longitudinal magnetograms and Hα filtergrams. We find that the moving magnetic features:
    1. Are associated only with decaying sunspots surrounded entirely or in part by a zone without a permanent vertical magnetic field.
    2. Appear first at or slightly beyond the outer edge of the parent sunspot regardless of the presence or absence of a penumbra.
    3. Move approximately radially outward from sunspots at about 1 km s?1 until they vanish or reach the network.
    4. Appear with both magnetic polarities from sunspots of single polarities but appear with a net flux of the same sign as the parent sunspot.
    5. Transport net flux away from the parent sunspots at the same rates as the flux decay of the sunspots.
    6. Tend to appear in opposite polarity pairs.
    7. Appear to carry a total flux away from sunspots several times larger than the total flux of the sunspots.
    8. Produce only a very faint emmission in the core of Hα.
    A model to help understand the observations is proposed.  相似文献   

    5.
    An observational study of maps of the longitudinal component of the photospheric fields in flaring active regions leads to the following conclusions:
    1. The broad-wing Hα kernels characteristic of the impulsive phase of flares occur within 10″ of neutral lines encircling features of isolated magnetic polarity (‘satellite sunspots’).
    2. Photospheric field changes intimately associated with several importance 1 flares and one importance 2B flare are confined to satellite sunspots, which are small (10″ diam). They often correspond to spot pores in white-light photographs.
    3. The field at these features appears to strengthen in the half hour just before the flares. During the flares the growth is reversed, the field drops and then recovers to its previous level.
    4. The magnetic flux through flare-associated features changes by about 4 × 1019 Mx in a day. The features are the same as the ‘Structures Magnétiques Evolutives’ of Martres et al. (1968a).
    5. An upper limit of 1021 Mx is set for the total flux change through McMath Regions 10381 and 10385 as the result of the 2B flare of 24 October, 1969.
    6. Large spots in the regions investigated did not evince flux changes or large proper motions at flare time.
    7. The results are taken to imply that the initial instability of a flare occurs at a neutral point, but the magnetic energy lost cannot yet be related to the total energy of the subsequent flare.
    8. No unusual velocities are observed in the photosphere at flare time.
      相似文献   

    6.
    An analysis of the data concerning high-velocity stars from Eggen's catalogue aimed at a determination of the approximate slope of the mass function for the spherical component of our Galaxy, and at estimating the local circular velocity, as well as the local rotation velocity, as by-products, has been performed. Our conclusions are that:
    1. A linear dependence of the mass on the radius is very likely;
    2. the value of the limiting radius is most likely equal to (40±10) kpc;
    3. the two local velocities are approximately equal to each other, being both equal to (230±30) km s?1;
    4. the local escape velocity appears to be most likely equal to (520±30) km s?1;
    5. the total mass of a corona, obtained in this way, is (5±1)×1011 M ⊙.
      相似文献   

    7.
    In a previous paper (Stellmacher, 1981, hereafter mentioned as Paper I), we have given an algorithm for the construction of periodic orbits in a rotating frame, for satellites around an oblate planet. In the present paper, we apply this theory to the Mimas-Tethys case; we obtain the following results:
    1. Without resonance, it is possible to find a rotating system in which the solution is a periodic one. The angular velocity of this rotating frame is calculated as function of the masses of the two satellites.
    2. Including the resonant terms and assuming an exact commensurability of the implied frequencies, we demonstrate that the condition for periodic solutions in the rotating system as defined in (a) is: the initial position of the satellites at conjunction lies on an axis defined by (Ω1+Ω2)/2 or (Ω1+Ω2)/2 + π/2;Ω1 and Ω2 are the longitudes of the ascending nodes of the satellite's orbits. The solution still is a periodic one, thus all the conjunction occur in either axis.
    3. In the Mimas Tethys case there is only approximately commensurability between these frequencies. The two satellites are considered as oscillators whose amplitudes and phases are functions of time. The equation of the libration can be established; we find the usual form, but for each satellite the generating solution is a periodic solution (as defined in Paper I), but not a Keplerian one. It follows a determination of the masses which slightly differs from that given by Kozai (1957), when the same values of the observed quantities are used for calculations.
    4. The equation of the libration is: $$\ddot z + n_1^2 h^2 \sin z + n_1 q\dot z\sin z = 0$$
      相似文献   

    8.
    We present a broad range of complementary observations of the onset and impulsive phase of a fairly large (1B, M1.2) but simple two-ribbon flare. The observations consist of hard X-ray flux measured by the SMM HXRBS, high-sensitivity measurements of microwave flux at 22 GHz from Itapetinga Radio Observatory, sequences of spectroheliograms in UV emission lines from Ov (T ≈ 2 × 105 K) and Fexxi (T ≈ 1 × 107 K) from the SMM UVSP, Hα and Hei D3 cine-filtergrams from Big Bear Solar Observatory, and a magnetogram of the flare region from the MSFC Solar Observatory. From these data we conclude:
    1. The overall magnetic field configuration in which the flare occurred was a fairly simple, closed arch containing nonpotential substructure.
    2. The flare occurred spontaneously within the arch; it was not triggered by emerging magnetic flux.
    3. The impulsive energy release occurred in two major spikes. The second spike took place within the flare arch heated in the first spike, but was concentrated on a different subset of field lines. The ratio of Ov emission to hard X-ray emission decreased by at least a factor of 2 from the first spike to the second, probably because the plasma density in the flare arch had increased by chromospheric evaporation.
    4. The impulsive energy release most likely occurred in the upper part of the arch; it had three immediate products:
    1. An increase in the plasma pressure throughout the flare arch of at least a factor of 10. This is required because the Fexxi emission was confined to the feet of the flare arch for at least the first minute of the impulsive phase.
    2. Nonthermal energetic (～ 25 keV) electrons which impacted the feet of the arch to produce the hard X-ray burst and impulsive brightening in Ov and D3. The evidence for this is the simultaneity, within ± 2 s, of the peak Ov and hard X-ray emissions.
    3. Another population of high-energy (～100keV) electrons (decoupled from the population that produced the hard X-rays) that produced the impulsive microwave emission at 22 GHz. This conclusion is drawn because the microwave peak was 6 ± 3 s later than the hard X-ray peak.
      相似文献   

    9.
    We have investigated how the gradients of temperature and expansion velocities will change the emergent profiles from an extended medium in spherical symmetry. Variation of the source function and expansion velocities are assumed. The following variations of temperature are employed:
    1. T(r) ; T0 (isothermal case)
    2. T(r) ; T0(r/r0)1/2
    3. T(r) ; T0(r/r0)-1
    4. T(r) ; T0(r/r0)-2
    5. T(r) ; T0(r/r0)-3
    The profiles calculated present an interesting feature of broadening.  相似文献   

    10.
    We examine the propagation of Alfvén waves in the solar atmosphere. The principal theoretical virtues of this work are: (i) The full wave equation is solved without recourse to the small-wavelength eikonal approximation (ii) The background solar atmosphere is realistic, consisting of an HSRA/VAL representation of the photosphere and chromosphere, a 200 km thick transition region, a model for the upper transition region below a coronal hole (provided by R. Munro), and the Munro-Jackson model of a polar coronal hole. The principal results are:
    1. If the wave source is taken to be near the top of the convection zone, where n H = 5.2 × 1016 cm?3, and if B ⊙ = 10.5 G, then the wave Poynting flux exhibits a series of strong resonant peaks at periods downwards from 1.6 hr. The resonant frequencies are in the ratios of the zeroes of J 0, but depend on B ⊙, and on the density and scale height at the wave source. The longest period peaks may be the most important, because they are nearest to the supergranular periods and to the observed periods near 1 AU, and because they are the broadest in frequency.
    2. The Poynting flux in the resonant peaks can be large enough, i.e. P ⊙ ≈ 104–105 erg cm?2s?1, to strongly affect the solar wind.
    3. ¦δv¦ and ¦δB¦ also display resonant peaks.
    4. In the chromosphere and low corona, ¦δv ≈ 7–25 kms?1 and ¦δB¦ ≈0.3–1.0 G if P ⊙≈104-105 erg cm?2s?1.
    5. The dependences of ¦δv¦ and ¦δB¦ on height are reduced by finite wavelength effects, except near the wave source where they are enhanced.
    6. Near the base, ¦δB¦ ≈ 350–1200 G if P ⊙ ～- 104–105. This means that nonlinear effects may be important, and that some density and vertical velocity fluctuations may be associated with the Alfvén waves.
    7. Below the low corona most wave energy is kinetic, except near the base where it becomes mostly magnetic at the resonances.
    8. ?0 < δv 2 > v A or < δB 2 > v A/4π are not good estimators of the energy flux.
    9. The Alfvén wave pressure tensor will be important in the transition region only if the magnetic field diverges rapidly. But the Alfvén wave pressure can be important in the coronal hole.
      相似文献   

    11.
    The jet/grain model proposed by Ramatyet al. (1984, hereafter abbreviated as RKL) for production of the narrow gamma-ray lines reported from SS433 is examined and shown to be untenable on numerous grounds. Most importantly:
    1. The huge Coulomb collisional losses (W c?2×1041 erg s?1) from the jet, which would necessarily accompany non-thermal production of the gamma rays, demands a jet acceleration/collimation process acting over a very long range and with a power at least 102 times the Eddington limit for any stellar object.
    2. There is a collisional thick target limit (irrespective of jet mass) to the gamma ray yield per interstellar proton. Consequently, the gamma-ray data demand an improbably high interstellar density (?109 cm?3).
    3. For the grains to be kept cool enough (?3000 K) to survive the heating rateW c either by radiation or jet expansion would demand a ‘jet’ wider than its length and so inconsistent with narrow lines. In the case of radiative cooling, the resultant IR flux would exceed the observed values by a factor ?104.
    4. Light scattered on the jet grain mass required would be highly polarized, contrary to observations, unless the jet was optically thick to grains, again precluding their radiative cooling.
    5. To avoid unacceptable precessional broadening of the gamma-ray lines demands an emitting jet length ?0.5 days atv=0.26c. This increases the necessary mass loss rate by a factor ?10 over the values obtained by RKL who assumed a 4-day ‘flare’.
    6. The model also predicts rest energy gamma-ray lines which are not observed.
      相似文献   

    12.
    This paper outlines the problems of the quasi-steady matter-antimatter boundary layers discussed in Klein-Alfvén's cosmological theory, and a crude model of the corresponding ambiplasma balance is presented:
    1. At interstellar particle densities, no well-defined boundary layer can exist in presence of neutral gas, nor can such a layer be sustained in an unmagnetized fully ionized ambiplasma.
    2. Within the limits of applicability of the present model, sharply defined boundary layers are under certain conditions found to exist in a magnetized ambiplasma. Thus, at beta values less than unity, a steep pressure drop of the low-energy components of matter and antimatter can be balanced by a magnetic field and the electric currents in the ambiplasma.
    3. The boundary layer thickness is of the order of 2x 0?10/BT 0 1/4 metres, whereB is the magnetic field strength in MKS units andT 0 the characteristic temperature of the low-energy components in the layer.
      相似文献   

    13.
    The properties of rapidly changing inhomogeneities visible in the H and K lines above sunspot umbrae are described. We find as properties for these ‘Umbral Flashes’:
    1. A lifetime of 50 sec. The light curve is asymmetrical, the increase is faster than the decrease in brightness.
    2. A diameter ranging from the resolution limit up to 2000 km.
    3. A tendency to repeat every 145 sec.
    4. A ‘proper motion’ of 40 km/sec generally directed towards the penumbra.
    5. A Doppler shift of 6 km/sec.
    6. A magnetic field of 2100 G.
    7. A decrease in this field of 12 G/sec. This decrease is probably related to the flash motion.
    8. At any instant an average of 3–5 flashes in a medium-sized umbra. A weak feature often persists in the umbra after the flash. This post-flash structure initially shows a blue shift, but 100–120 sec after the flash, it shows a rapid red shift just before the flash repeats.
      相似文献   

    14.
    Celebrating the diamond jubilee of the Physics Research Laboratory (PRL) in Ahmedabad, India, we look back over the last six decades in solar physics and contemplate on the ten outstanding problems (or research foci) in solar physics:
    1. The solar neutrino problem
    2. Structure of the solar interior (helioseismology)
    3. The solar magnetic field (dynamo, solar cycle, corona)
    4. Hydrodynamics of coronal loops
    5. MHD oscillations and waves (coronal seismology)
    6. The coronal heating problem
    7. Self-organized criticality (from nanoflares to giant flares)
    8. Magnetic reconnection processes
    9. Particle acceleration processes
    10. Coronal mass ejections and coronal dimming
    The first two problems have been largely solved recently, while the other eight selected problems are still pending a final solution, and thus remain persistent Challenges for Solar Cycle 24, the theme of this jubilee conference.  相似文献   

    15.
    In this paper we review the drift theory of charged particles in electric and magnetic fields. No new physical interpretations are added to this classical topic, but through an alternative, simplified derivation of the guiding centre velocity, several complexities are eliminated and possible misconceptions of the theory are clarified. It is shown that:
    1. The curvature/gradient drift velocity in the magnetic field, averaged over a particle distribution function is to lowest order in the direction of?×B/B 2, while the average particle velocity is in the direction ofB×? P withP the scalar particle pressure.
    2. These drift directions are correct for first-order expansions of the particle distribution function, and only second-order or higher expansions change these directions.
    3. The?×B/B 2 drift, which is the standard gradient plus curvature drift, and which is usually considered as a ‘single particle’ drift, need not be ‘reconciled’ with theB×? P, or ‘macroscopic, collective’ drift, as is often asserted in the literature. They are in fact related per definition and we show how.
    4. When viewed in fixed momentum intervals (p,p+dp), the so-called Compton-Getting factor enters into the electric field (E×B)/B 2 drift term.
    5. The results are independent of the scale length of variation ofE andB, in contrast to existing drift theory. We discuss the implications of this result for three important cases.
      相似文献   

    16.
    J. J. Aly 《Solar physics》1992,138(1):133-162
    Some useful properties of a finite energy, constant-α, force-free magnetic field B α occupying a half-space D are presented. In particular:
    1. Fourier and Green representations of B α are obtained and used to derive conditions for the existence and uniqueness of a B α having a given normal component B z on the boundary ?D.
    2. The asymptotic behaviour of B α at infinity as well as stability results against changes in the boundary condition on ?D and in the value of α are established.
    3. The energy of B α is shown to be smaller than the energy of the open field having the same B z on ?D, thus confirming an earlier conjecture (Aly, 1984).
    4. B α is proved to not be a Taylor-Heyvaerts-Priest state, in spite of the fact that its relative helicity H is finite and that it is the only solution of the Lagrange-Euler equation associated with the problem of minimizing the energy among all the fields having the same value of H and the same B z on ?D.
      相似文献   

    17.
    1. Introduction and Survey. The method for studying the structure and evolution of the solar system is discussed. It is pointed out that theories that account for the origin of planets alone are basically insufficient. Instead one ought to aim for a general theory for the formation of secondary bodies around a central body, applicable both to planet and satellite formation. A satisfactory theory should not start from assumed properties of the primitive Sun, which is a very speculative subject, but should be based on an analysis of present conditions and a successive reconstruction of the past states.
    2. Orbits of Planets and Satellites. As a foundation for the subsequent analysis, the relevant properties of planets and satellites are presented.
    3. The Small Bodies. The motion of small bodies is influenced by non-gravitational forces. Collisions (viscosity) are of special importance for the evolution of the orbits. It is pointed out that the focusing property of a gravitational field (which has usually been neglected) leads to the formation of jet streams. The importance of this concept for the understanding of the comet-meteoroid relations and the structure of the asteroidal belt is shown.
    4. Resonance Structure. A survey is given of the resonances in the solar system and their possible explanation. It is concluded that in many cases the resonances must already be produced at the times when the bodies formed. It is shown that resonance effects put narrow limits on the post-accretional changes of orbits.
    5. Spin and Tides. Tidal effects on planetary spins and satellite orbits are discussed. It is very doubtful if any satellite except the Moon and possibly Triton has had its orbit changed appreciably by tidal effects. The isochronism of planetary and asteroidal spins is discussed, as well as its bearing on the accretional process.
    6. Post-accretional Changes in the Solar System. The stability of the solar system and upper limits for changes in orbital and spin data are examined. It is concluded that much of the present dynamic structure has direct relevance to the primordial processes.
      相似文献   

    18.
    Coordinates of polar faculae have been measured and processed using daily photoheliograms of the Kislovodsk Station of the Pulkovo observatory with the final goal of studying their latitude distribution during the solar cycles 20–21. The results obtained are as follows:
    1. The first polar faculae emerge immediately after the polarity inversion of the solar magnetic field at the latitudes from 40° to 70° with the average ?-55°.
    2. The zone of the emergence of polar faculae migrates poleward during the period between the neighbouring polarity inversions of the solar magnetic field. This migration is about 20° for 8 years, which corresponds to a velocity of 0.5 m s-1.
    3. The maximum number of polar faculae was reached at the activity minimum (1975–1976).
    4. The last polar faculae were observed in the second half of 1978 at the latitudes from 70° to 80°.
      相似文献   

    19.
    Photoelectric measurements of Doppler shifts of various Fraunhofer lines obtained with the Capri magnetograph were analysed. The height dependence of the supergranular and oscillatory motions, as well as the two dimensional structure of these velocity fields is investigated. The most interesting results are the following:
    1. The oscillatory and supergranular motions are still clearly present in very deep photospheric layers as detected e.g. by means of the Ci line at 5380.3 Å.
    2. Whereas the vertical motions (both of oscillation and supergranulation) increase with height, the horizontal component of the supergranular flow is found to be decreasing slightly.
    3. Aperiodic horizontal motions are observed in the photospheric layers, which are probably connected with the process of excitation of the oscillatory field.
    4. There is no simple way of describing the oscillatory field in terms of independently oscillating ‘cells’, since the two-dimensional pattern changes its appearance drastically already in a fraction of one oscillation period.
    5. The correlation obtained by previous observers between vertical stationary motions, the chromospheric network and magnetic fields in particular is confirmed.
      相似文献   

    20.
    We report the results of the application of our approach to study the behavior of solar activity in the past, where:
  • When reconstructing the variations of solar activity, geomagnetic parameters, and the interplanetary magnetic field in the past we select a sequence of increasing time scales, which can be naturally represented by the potentials of available observational data. We select a total of four time scales: 150–200 years, 400 years, 1000 years, and 10000 years.
  • When constructing the series of each successive (in terms of length) time scale we use the data of the previous time scale as reference data.
  • We abandon, where possible, the series of traditional statistical parameters in favor of the series of physical parameters.
  • When deriving the relations between any parameters of solar activity, geomagnetic disturbance, and the interplanetary magnetic field, we take into account the differential nature of relations on different time scales. To this end, we use the earlier proposed MSR and DPS methods.
  • To verify the resulting reconstructions, we use the “principle of witnesses”, which uses independent (in some cases, indirect) information as initial data.
    •   相似文献   

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