相关论文: Temporal Variations of High-Degree Solar p-Modes u…

Using the Hilbert-Huang transform technique, we investigate the midrange periodicities in solar radio flux at 2800 MHz (F10.7) and sunspot areas (SAs) from February 1, 1947 to September 30, 2016. The following prominent results are found:…

Seismic analyses of the CoRoT target HD 49933 have revealed a magnetic cycle. Further insight reveals that frequency shifts of oscillation modes vary as a function of frequency, following a similar pattern to that found in the Sun. In this…

The apparently unusual behaviour of the TSI during the most recent minimum of solar activity has been interpreted as evidence against solar surface magnetism as the main driver of the secular change in the TSI. We test claims that the…

The level of solar magnetic activity, as exemplified by the number of sunspots and by energetic events in the corona, varies on a wide range of time scales. Most prominent is the 11-year solar cycle, which is significantly modulated on…

Context. We present the first high-cadence multi-wavelength radial-velocity observations of the Sun-as-a-star, carried out during 57 consecutive days using the stellar \'echelle spectrograph at the Hertzsprung SONG Telescope operating at…

We analyze more than 5000 days of high-quality Sun-as-a-star, radial velocity GOLF and photometric VIRGO/SPM helioseismic observations to extract precise estimates of the visibilities of the low-degree p modes and the m-height ratios of the…

While it has been relatively easy to determine solar-cycle related changes in solar dynamics, determining changes in structure in the deeper layers of the Sun has proved to be difficult. By using helioseismic data obtained over two solar…

Oscillations were observed across the whole solar disk using the Doppler shift and line depth of spectral lines from the CO molecule near 4666~nm with the National Solar Observatory's McMath/Pierce solar telescope. Power, coherence, and…

We present results on the structure of the near-surface layers of the Sun obtained by inverting frequencies of high-degree solar modes from "ring diagrams". We have results for eight epochs between June 1996 and October 2003. The…

The high-quality, full-disk helioseismic observations continuously collected by the spectrophotometer GOLF and the three photometers VIRGO/SPMs onboard the SoHO spacecraft for 17 years now (since April 11, 1996, apart from the SoHO…

With the ultimate aim of using the fundamental or $f$-mode to study helioseismic aspects of turbulence-generated magnetic flux concentrations, we use randomly forced hydromagnetic simulations of a piecewise isothermal layer in two…

Aims. With the Solar Optical Telescope on Hinode, we investigate the basic properties of high-degree solar oscillations observed at two levels in the solar atmosphere, in the G-band (formed in the photosphere) and in the Ca II H line…

Herein we adopt a multi-scale dynamical spectral analysis technique to compare and study the dynamical evolution of the harmonic components of the overlapping ACRIMSAT/ACRIM3, SOHO/VIRGO and SORCE/TIM total solar irradiance (TSI) records…

We have used data collected by the Birmingham Solar-Oscillations Network (BiSON) to perform a helioseismic diagnosis of changes to the Sun's internal structure between four successive solar cycle minima, beginning with the minimum at the…

Some observations suggest that solar spicules show small amplitude and high frequency oscillations of magneto-acoustic waves, which arise from photospheric granular forcing. We apply the method of MHD seismology to determine the period of…

Accurate determination of the rotation rate in the radiative zone of the sun from helioseismic observations requires rotational frequency splittings of exceptional quality as well as reliable inversion techniques. We present here inferences…

Solar activity has significantly changed over the last two Schwabe cycles. After a long and deep minimum at the end of Cycle 23, the weaker activity of Cycle 24 contrasts with the previous cycles. In this work, the response of the solar…

We recently presented evidences (Rajaguru et al. 2012) that seismic halos around expanding magnetic structures in the lower solar atmosphere are related to the acoustic to magnetoacoustic wave conversions, using multi-height data from…

Measurements of Ra-226 activity from eight HPGe gamma ray detectors at the NC State University PULSTAR Reactor were analyzed for evidence of periodic variations, with particular attention to annual variations. All measurements were made…

Temporal variations of the structure and the rotation rate of the solar tachocline region are studied using helioseismic data from the Global Oscillation Network Group (GONG) and the Michelson Doppler Imager (MDI) obtained during the period…