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Related papers: GOLF: a new proxy for solar magnetism

200 papers

Asteroseismic modelling is crucial for upcoming missions like PLATO, CubeSpec, and Roman. Despite significant progress, discrepancies between observations and theoretical predictions introduce biases in stellar characterisation at the…

Tilt angles of close to 30,600 sunspots are determined using Mount Wilson daily averaged magnetograms taken from 1974 to 2012, and MDI/SoHO magnetograms taken from 1996 to 2010. Within a cycle, more than 90% of sunspots have a normal…

Solar and Stellar Astrophysics · Physics 2015-06-11 Jing Li , Roger K. Ulrich

In this paper, we analyze the probability density function (PDF) of solar wind velocity and proton density, based on generalized thermostatistics (GT) approach, comparing theoretical results with observational data. The time series analyzed…

The solar mean magnetic field (SMMF) provided by the Wilcox Solar Observatory (WSO) is compared with the SMMF acquired by the \textit{Helioseismic and Magnetic Imager} (HMI) onboard the \textit{Solar Dynamic Observatory} (SDO). We found…

Solar and Stellar Astrophysics · Physics 2016-08-18 A. S. Kutsenko , V. I. Abramenko

The study of low-degree high-frequency waves in the Sun can provide new insight into the dynamics of the deeper layers of the Sun. Here, we present the analysis of the velocity observations of the Sun obtained from the Michelson and Doppler…

Solar and Stellar Astrophysics · Physics 2010-03-12 Brajesh Kumar , Savita Mathur , R. A. Garcia , P. Venkatakrishnan

The Sun-as-a-star helioseismic spectrophotometer GOLF and photometer VIRGO instruments onboard the SoHO spacecraft are collecting high-quality, continuous data since April 1996. We analyze here these unique datasets in order to investigate…

Solar and Stellar Astrophysics · Physics 2014-11-04 D. Salabert , R. A. Garcia , A. Jimenez

Previously unobservable mirror asymmetry of the solar magnetic field -- a key ingredient of the dynamo mechanism which is believed to drive the 11-year activity cycle -- has now been measured. This was achieved through systematic monitoring…

Solar and Stellar Astrophysics · Physics 2015-05-14 Hongqi Zhang , T. Sakurai , A. Pevtsov , Yu Gao , Haiqing Xu , D. D. Sokoloff , K. Kuzanyan

Solar photospheric magnetic field plays a dominant role in the variability of total solar irradiance (TSI). The modulation of magnetic flux at six specific ranges on TSI is characterized for the first time. The daily flux values of magnetic…

Solar and Stellar Astrophysics · Physics 2018-04-18 J. C. Xu , D. F. Kong , F. Y. Li

The detection of gravity modes is expected to give us unprecedented insights into the inner dynamics of the Sun. Within this framework, predicting their amplitudes is essential to guide future observational strategies and seismic studies.…

Solar and Stellar Astrophysics · Physics 2021-06-09 C. Pinçon , T. Appourchaux , G. Buldgen

By using the unique database of SOHO/MDI full disk magnetograms from 1996 September to 2011 January, covering the entire solar cycle 23, we analyze the time-variability of the solar magnetic flux spectrum and study the properties of…

Solar and Stellar Astrophysics · Physics 2015-06-18 C. l. Jin , J. X. Wang

A novel time--frequency technique, called the synchrosqueezing transform (SST), is used to investigate the midterm periodic variations of magnetic fields on the solar surface. The Magnetic Plage Strength Index (MPSI) and the Mount Wilson…

Solar and Stellar Astrophysics · Physics 2018-03-22 Song Feng , Lan Yu , Feng Wang , Hui Deng , Yunfei Yang

The GOLF resonant scattering spectrophotometer aboard SoHO has now provided 15 years of continuous high precision Sun-as-a-star radial-velocity measurements. This length of time series provides very high resolution in the frequency domain…

Solar and Stellar Astrophysics · Physics 2011-10-04 Guy R. Davies , Rafael A. García

Since the detection of the asymptotic properties of the dipole gravity modes in the Sun, the quest to find individual gravity modes has continued. An extensive and deeper analysis of 14 years of continuous GOLF/SoHO observational data,…

Gravity modes in the Sun have been long searched during the past decades. Using their asymptotic properties Garcia et al. (2007) found the signature of the dipole g modes analyzing an spectral window between 25 and 140 muHz of velocity…

Astrophysics · Physics 2008-10-10 A. Jimenez , R. A. Garcia

The solar magnetism is no more considered as a purely superficial phenomenon. The SoHO community has shown that the length of the solar cycle depends on the transition region between radiation and convection. Nevertheless, the internal…

The solar activity displays variability and periodic behaviours over a wide range of timescales, with the presence of a most prominent cycle with a mean length of 11 years. Such variability is transported within the heliosphere by solar…

Solar and Stellar Astrophysics · Physics 2022-10-17 R. Reda , L. Giovannelli , T. Alberti

For the first time we reconstruct the magnetic helicity density of global axisymmetric field of the Sun using method proposed by Brandenburg et al. (2003) and Pipin et al. (2013). To determine the components of the vector potential, we…

Solar and Stellar Astrophysics · Physics 2015-06-18 V. V. Pipin , A. A. Pevtsov

Observations of magnetic helicity transportation through the solar photosphere reflect the interaction of turbulent plasma movements and magnetic fields in the solar dynamo process. In this chapter, we have reviewed the research process of…

Solar and Stellar Astrophysics · Physics 2023-11-14 Hongqi Zhang , Shangbin Yang , Haiqing Xu , Xiao Yang , Jie Chen , Jihong Liu

Measurements from the Mount Wilson Observatory (MWO) are used to study the long-term variations of sunspot field strengths from 1920 to 1958. Following a modified approach similar to that in Pevtsov et al. (2011), for each observing week we…

Solar and Stellar Astrophysics · Physics 2013-01-28 Alexei A. Pevtsov , Luca Bertello , Andrey G. Tlatov , Ali Kilcik , Yury A. Nagovitsyn , Edward W. Cliver

The data of sunspot numbers, sunspot areas and solar flare index during cycle 23 are analyzed to investigate the intermediate-term periodicities. Power spectral analysis has been performed separately for the data of the whole disk, northern…

Solar and Stellar Astrophysics · Physics 2009-11-16 Bhuwan Joshi , P. Pant , P. K. Manoharan