The history of modern helioseismology is only ten years old. In 1975 F-L Deubner separated for the first time the spatial and temporal pro perties of the solar five-minute oscillations, and was thus able to measure the dispersion relation for high-degree acoustic modes (p modes). The diagnostic value of these observations was appreciated immediately. Indeed, by comparing the observed relation with computations that had already been carried out by R.K. Ulrich, and subsequently by H. Ando and Y. Osaki, it was recognised that contemporary solar models that had been constructed with the low observed neutrino flux in mind were too hot in their outer layers. Moreover, their convection zones were too shallow. Since that time the observations have improved. There is now good reason to suppose that a sufficiently careful analysis will lead to a direct determination of the helium abundance in the solar convection zone, especially when foreseeable further improvements in the observations have been achieved. The data will also provide useful diagnostics of the uncertain equation of state of partially ionized plasmas, and they might also enable us to measure the large-scale structure of the convec tive flow.
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ISBN-13
978-94-009-4608-8 (9789400946088)
DOI
10.1007/978-94-009-4608-8
Schweitzer Klassifikation
Properties of solar oscillations.- Theoretical aspects of helio- and asteroseismology.- Observations of low-degree p-mode oscillations in 1984.- Another reason to search for solar g-modes and new limits from solar ellipticity measurements.- Phase studies of solar 5 min oscillations.- Observations of gravity waves in the solar atmosphere.- Is there an anisotropy of p-modes?.- Influence of spatial filtering on possible anisotropies in solar oscillations.- The detection of global convective wave flows on the sun.- First evidence of a large-scale circulation in the solar convection zone.- Solar Doppler shifts: sources of continuous spectra.- Comments on techniques for spectral deconvolution.- Sound speed in the interior of solar models.- Asymptotic sound-speed inversions.- Asymptotics and quantum chaos in stellar oscillations.- An improved asymptotic formula for solar gravity-mode periods.- Solar g modes: a method to find the depth of the convective envelope.- The influence of convection theory uncertainties on the deduction of the speed of sound in the solar interior.- Measuring the sun's internal rotation using solar p-mode oscillations.- Rotational splitting of ?= 1 p modes.- Linewidth and rotational splitting of low degree modes in the 5 minute region.- Solar core rotation: a down to earth view.- The internal rotation of the sun.- On the solar rotation.- The internal rotation of the sun.- Magnetic torques and differential rotation.- Internal rotation of the sun as a consequence of instabilities in the radiative interior.- Finite amplitude limit of the 3He instability.- Is the existence of a strong magnetic field in the sun'score plausible?.- Progress report on helium abundance determination.- On wave reflection or absorption at hydromagnetic critical levels.- Onumbral oscillations as a sunspot diagnostic.- Change of solar oscillation eigenfrequencies with the solar cycle.- Long period variations in the solar diameter.- The 1984 solar oscillation program of the Mt. Wilson 60-foot tower.- The K 769.9 nm line profile.- Ground based measurements of global solar intensity oscillations.- A liquid crystal modulator.- A Fabry-Perot based stellar seismometer.- Applications of the magneto-optical filter to stellar pulsation measurements.- A new Fabry-Perot radial velocity spectrometer.- Interferometric stellar oscillation spectrometry.- Absolute astronomical accelerometry.- Evidence for p-modes on Alpha Centauri and Procyon.- A review of the rapidly oscillating Ap stars.- Asterseismology for certain Ap stars.- Nonradial modes in line-profile variable stars.- Observational properties of nonradial oscillations in early-type stars and their possible effect on mass loss: the example of z Puppis (04 If).- Southern ZZ Ceti stars.- How well do we know stellar parameters?.
