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Javaraiah, J.

doi:10.1023/a:1022912430585

Cited by 79 publications

(38 citation statements)

References 48 publications

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“…Since the meridional circulation acts as a clock controlling the cycle length, this also could explain the increase in the period. This scenario is also valid for changes in the differential rotation of the Sun and agrees with previous works (Javaraiah 2003;Antia et al 2008).…”

Section: Discussionsupporting

confidence: 92%

A Low‐Order Solar Dynamo Model: Inferred Meridional Circulation Variations Since 1750

Passos¹,

Lopes²

2008

Astrophysical Journal

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In this work we present the possible variations that the meridional circulation of the Sun might have undergone during the last 250 years. In order to do this, we reduce an -dynamo to a low-order system that focuses on the time evolution of one of the solar magnetic field components. Afterward we used a method based on the analysis of phase space of the superficial toroidal magnetic field to infer changes in the superficial meridional circulation. We used sunspot numbers to build a time series that approximately represents the magnetic field behavior. After reconstructing the time series' phase space we assume equilibrium solutions for each solar cycle and we fit them to our model. The resulting fit parameters are shown to depend on background quantities of the theoretical model, such as magnetic diffusivity, differential rotation, meridional circulation, etc. The methodology presented here allows one to extract information about the meridional circulation average behavior, and possibly other parameters, from more that 250 years of sunspot number observations.

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Section: Discussionsupporting

confidence: 92%

A Low‐Order Solar Dynamo Model: Inferred Meridional Circulation Variations Since 1750

Passos¹,

Lopes²

2008

Astrophysical Journal

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“…The rotation rate of the interior and the surface are coupled with the rotation rate of the solar atmosphere, especially the corona. Although there is a general consensus regarding the interior rotation as inferred from helioseismology (Dalsgaard & Schou 1988;Thompson et al 1996Thompson et al , 2003 and references therein; Antia et al 1998;Howe 2009;Antia & Basu 2010), surface rotation rates as derived from sunspots (Newton & Nunn 1951;Howard et al 1984;Balthasar et al 1986;Shivaraman et al 1993;Javaraiah 2003), Doppler velocity (Howard & Harvey 1970;Howard & La Bonte 1980;Ulrich et al 1988;Snodgrass & Ulrich 1990), and magnetic activity features (Wilcox & Howard 1970;Snodgrass 1983;Komm et al 1993), there is no such consensus (see also Li et al 2012) on the magnitude and form of the rotation law for features in the corona.…”

Section: Introductionmentioning

confidence: 99%

Rotation Rates of Coronal Holes and Their Probable Anchoring Depths

Hiremath

Hegde

2013

ApJ

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From 2001From -2008, we use full-disk, SOHO/EIT 195 Å calibrated images to determine latitudinal and day-to-day variations of the rotation rates of coronal holes (CHs). We estimate the weighted average of heliographic coordinates such as latitude and longitude from the central meridian on the observed solar disk. For different latitude zones between 40• north and 40• south, we compute rotation rates and find that, irrespective of their area, the number of days observed on the solar disk, and their latitudes, CHs rotate rigidly. Combined for all the latitude zones, we also find that CHs rotate rigidly during their evolution history. In addition, for all latitude zones, CHs follow a rigid body rotation law during their first appearance. Interestingly, the average first rotation rate (∼438 nHz) of CHs, computed from their first appearance on the solar disk, matches the rotation rate of the solar interior only below the tachocline.

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“…For the investigation of possible variations in the solar rotation, the Greenwich data set was used by Balthasar & Wöhl (1980), Arévalo et al (1982), and Balthasar et al (1986); the Kanzelhöhe data set by Lustig (1983); the Mt. Wilson data set by Gilman & Howard (1984) and by Hathaway & Wilson (1990); the Mitaka data set by Kambry & Nishikawa (1990); the Suzuka data set by Suzuki (1998); the extended Greenwich data set by Pulkkinen & Tuominen (1998), Javaraiah (2003), Zuccarello & Zappalá (2003), Javaraiah et al (2005), Javaraiah & Ulrich (2006), and Brajša et al (2006Brajša et al ( , 2007; the Kodaikanal data set by Gupta et al (1999); and the Abastumani data set by Khutsishvili et al (2002). Also, temporal variations in the solar rotation were studied using other Article published by EDP Sciences A17, page 1 of 6…”

Section: Introductionmentioning

confidence: 99%