This review systematically explores various strategies aimed at enhancing charge transfer different levels—bulk, surface, and interfaces of hematite. The examination encompasses diverse approaches, assesses their impact on mitigating the identified issues.

Abstract Chromospheric differential rotation is a key component in comprehending the atmospheric coupling between chromosphere and photosphere at different phases of solar cycle. In this study, we therefore utilize newly calibrated multidecadal Ca ii K spectroheliograms (1907–2007) from Kodaikanal Solar Observatory (KoSO) to investigate using technique image cross-correlation. Our analysis yields chromospheric rate Ω( θ ) = (14.61 ± 0.04–2.18 0.37 <?CDATA ${\sin }^{2}\theta -1.10\pm...

Abstract The process of the Sun’s polar field cancellation reversal commences with emergence new cycle Hale’s polarity active regions. Once Sun undergoes reversal, typically occurring near peak solar activity, it begins accumulating seed for forthcoming cycle. In recent years, advective flux transport (AFT) model has proven highly effective in forecasting progression fields by leveraging observations surface flows and magnetic emergence. this study, we make use predictive capability AFT to...

The tilt of bipolar magnetic region (BMR) is crucial in the Babcock--Leighton process for generation poloidal field Sun. Based on thin flux tube model BMR formation, believed to be caused by Coriolis force acting rising strong toroidal from base convection zone (BCZ). We analyze dependence tilts using magnetograms Michelson Doppler Imager (MDI) (1996-2011) and Helioseismic Magnetic (HMI) (2010-2018). observe that distribution maximum ($B_{\rm max}$) BMRs bimodal. Its first peak at low...

Abstract One of the intriguing mechanisms Sun is formation bipolar magnetic regions (BMRs) in solar convection zone (CZ), which are observed as concentrated fields opposite polarity on photosphere. These BMRs tilted with respect to equatorial line, statistically increases latitude. The thin flux tube model, employing rise magnetically buoyant loops and their twist by Coriolis force, a popular paradigm for explaining BMRs. In this study, we assess validity model analyzing tracked BMR data...

The global rotational profile of the solar atmosphere and its variation at different layers, although crucial for a comprehensive understanding dynamics magnetic field, has been subject to contradictory results throughout past century. In this study, we thereby unify parts multi-thermal Solar by utilizing 13 years data in 7 wavelength channels Atmospheric Imaging Assembly (AIA) atop Dynamic Observatory (SDO). Using method image correlation, find that exhibits is up 4.18% 1.92% faster equator...

The Sun's polar magnetic field is pivotal in understanding solar dynamo processes and forecasting future cycles. However, direct measurements of the only available since 1970s. chromospheric Ca II K network index (PNI; fractional area regions above a certain latitude) has recently emerged as reliable proxy for fields. In this study, we derive PNI estimates from newly calibrated, rotation-corrected observations Kodaikanal Solar Observatory (1904-2007) modern data Rome Precision Photometric...

The polar magnetic field plays a crucial role in the solar dynamo model and contributes to predicting future cycles. However, continuous direct measurements of this have been available only since 1976, with data provided by Wilcox Solar Observatory (WSO). Recent findings suggest that Ca ii K Polar Network Index (PNI) can serve as promising proxy for estimating Sun. In study, we aim reconstruct pre-1976 period leveraging from Kodaikanal (KoSO; 1904-2007) modern observations Rome Precision...

Abstract The Sun’s polar magnetic field is pivotal in understanding solar dynamo processes and forecasting future cycles. However, direct measurements of the have only been available since 1970s. chromospheric Ca ii K network index (PNI; fractional area regions above a certain latitude) has recently emerged as reliable proxy for fields. In this study, we derive PNI estimates from newly calibrated, rotation-corrected observations Kodaikanal Solar Observatory (1904–2007) modern data Rome...

Abstract Global solar photospheric magnetic maps play a critical role in and heliospheric physics research. Routine magnetograph measurements of the field occur only along Sun–Earth line, leaving far side Sun unobserved. Surface flux transport (SFT) models attempt to mitigate this by modeling surface evolution field. While such have long been established community (with several releasing public full-Sun maps), none are open source. The Open-source Flux Transport (OFT) model seeks fill gap...

Abstract Bipolar magnetic regions (BMRs) provide crucial information about solar magnetism. They exhibit varying morphology and properties throughout their lifetime, studying these can valuable insights into the workings of dynamo. The majority previous studies have counted every detected BMR as a new one not been able to study full life history each BMR. To address this issue, we developed Automatic Tracking Algorithm for BMRs (AutoTAB) that tracks entire lifetime or disk passage. AutoTAB...

Full-disc Ca II K photographic observations of the Sun carry direct information about evolution solar-plage regions for more than a century and are therefore unique dataset solar-activity studies. For long time were barely explored, but recent digitisations multiple archives have allowed their extensive analysis. However, various studies reported diverse results partly due to insufficient quality digitised data. Furthermore, inhomogeneities been identified within individual archives, which,...

Kodaikanal Solar Observatory (KoSO) possesses one of world's longest and homogeneous records sunspot observations that span more than a century (1904-2017). Interestingly, these (originally recorded in photographic plates/films) were taken with the same setup over this entire time period which makes data unique best suitable for long-term solar variability studies. A large part data, between 1921-2011, digitized earlier catalog containing detected parameters (e.g., area location) was...

Abstract With over 100 yr of solar observations, the Kodaikanal Solar Observatory (KoSO) is a one-of-a-kind data repository in world. Among its many catalogs, “suncharts” at KoSO are particular interest. These suncharts (1904–2020) colored drawings different features, such as sunspots, plages, filaments, and prominences, made on papers with Stonyhurst latitude–longitude grid etched them. In this paper, we analyze unique by first digitizing each sunchart using an industry-standard scanner...

One of the intriguing mechanisms Sun is formation bipolar magnetic regions (BMRs) in solar convection zone which are observed as concentrated fields opposite polarity on photosphere. These BMRs tilted with respect to equatorial line, statistically increases latitude. The thin flux tube model, employing rise magnetically buoyant loops and their twist by Coriolis force, a popular paradigm for explaining BMRs. In this study, we assess validity model analyzing tracked BMR data obtained through...

ABSTRACT The Sun has a near-surface shear layer (NSSL), within which the angular velocity decreases rapidly with radius. We provide an explanation of this based on thermal wind balance equation. Since convective motions are not affected by solar rotation in top convection zone, we argue that temperature falls at same rate all latitudes layer. This makes term very large and centrifugal also to become it, giving rise NSSL. From values differential Ω(r &amp;lt; rc, θ) radii less than radius can...

Bipolar Magnetic Regions (BMRs) provide crucial information about solar magnetism. They exhibit varying morphology and magnetic properties throughout their lifetime, studying these can valuable insights into the workings of dynamo. The majority previous studies have counted every detected BMR as a new one not been able to study full life history each BMRs. To address this issue, we developed an Automatic Tracking Algorithm (AutoTAB) for BMRs, that tracks BMRs entire lifetime or disk passage....

Abstract A typical sunspot, as seen in white-light intensity images, has a two part structure: dark umbra and lighter penumbra. Such distinction primarily arises due to the different orientations of magnetic fields these regions. In this study, we use Kodaikanal digitized data archive analyze long-term evolution umbral penumbal area. We used an ‘automated algorithm’ uniquely identify sunspot (including calculation penumbra ratio) from images. Our analysis reveals that ratio increases...

Chromospheric differential rotation is a key component in comprehending the atmospheric coupling between chromosphere and photosphere at different phases of solar cycle. In this study, we therefore utilize newly calibrated multidecadal Ca II K spectroheliograms (1907-2007) from Kodaikanal Solar Observatory (KoSO) to investigate using technique image cross-correlation. Our analysis yields chromospheric rate $\Omega (\theta) = (14.61\pm 0.04 - 2.18\pm 0.37\sin^2{\theta} 1.10 \pm...

Abstract We present a theoretical model of the near-surface shear layer (NSSL) Sun. Convection cells deeper down are affected by Sun’s rotation, but this is not case in just below solar surface due to smallness convection there. Based on idea, we show that thermal wind balance equation (the basic theory meridional circulation which holds inside zone) can be solved obtain structure NSSL, matching observational data remarkably well.

The tilt of the bipolar magnetic region (BMR) is crucial in Babcock-Leighton process for generation poloidal field Sun. We extend work Jha et al. (2020) and analyze recently reported tracked BMR catalogue based on AutoTAB Sreedevi (2023) from Michelson Doppler Imager (1996-2011) Helioseismic Magnetic (2010-2018). Using information BMRs AutoTAB, we confirm that distribution bmax by not because are picked multiple times at different phases their evolution instead it also present if consider...

AutoTAB is a state-of-the-art, fully automatic algorithm that tracks the Bipolar Magnetic Regions (BMRs) in magnetogram observations. employs identified BMR regions from Line-of-Sight magnetograms MDI and HMI (1996--2022) to track BMRs through their evolution on nearside of Sun. enables us create comprehensive unique catalog tracked information 9232 mentioned time period. This dataset used study collective statistical properties particularly identify correct theory for formation. Here, we...