North South Asymmetry of Different Solar Activity Features During Solar Cycle 23

A study on North South (NS) asymmetry of different solar activity features (DSAF) such as solar proton events, solar active prominences, H alpha flare index, soft X ray flares, monthly mean sunspot area and monthly mean sunspot number were carried out from 1996 to 2008. It is found in our result that solar cycle 23 is magnetically weak compared to solar cycle 22. Study shows the Southern dominance of DSAF during the time period of study. During the rising phase of the cycle the numbers of DSAF approximately equal on the North and South Hemisphere. However, these activities tend to shift from Northern Hemisphere to Southern Hemisphere in between year 1998 to 1999. The statistical significance of the asymmetry time series using a chi square test of goodness of fit indicates that in most of the cases the asymmetry is highly significant, i.e., the asymmetry is a real feature in the NS distribution of DSAF.Comment: In this manuscript total 19 pages including 7 figures and 3 table

Study of Distribution and Asymmetry of Solar Active Prominences During Solar Cycle 23

In this paper we present the results of a study of the spatial distribution and asymmetry of solar active prominences (SAP) for the period 1996-2007 (solar cycle 23). For more meaningful statistical analysis we have analysed the distribution and asymmetry of SAP in two subdivisions viz. Group1 (ADF, APR, DSF, CRN, CAP) and Group2 (AFS, ASR, BSD, BSL, DSD, SPY, LPS). The north-south (N-S) latitudinal distribution shows that the SAP events are most prolific in the 21-30degree slice in the northern and southern hemispheres and east-west (E-W) longitudinal distribution study shows that the SAP events are most prolific (best visible) in the 81-90degree slice in the eastern and western hemispheres. It has been found that the SAP activity during this cycle is low compared to previous solar cycles. The present study indicates that during the rising phase of the cycle the number of SAP events were roughly equal on the north and south hemispheres. However, activity on the southern hemisphere has been dominant since 1999. Our statistical study shows that the N-S asymmetry is more significant then the E-W asymmetry.Comment: 21 pages 5 figures; Published online; 02 October, 2009; Solar Physics Journa

H⍺, EUV and UV analysis of an eruptive 3B/X1.2 flare

386-390The present paper presents observational results of an extremely energetic eruptive flare 3B/X1.2 from superactive region NOAA 10486. The observations were taken on 26 October 2003 with 15 cm Solar Tower Telescope at Aryabhatta Research Institute of Observational Sciences (ARIES). Hα observations of the flare show long multi ribbon eruptions along a large twisted (sigmoid) filament in a high gradient (~90º) magnetic field and shear. The evolution pattern of this flare is similar in EUV and UV. Four eruptive centers or kernels in Hα have been chosen, wherein K₁ shows two prominent peaks while K₃ exhibits only one prominent peak with gradual decay. The analysis shows that this is a classical long duration event (LDE). The results have been discussed in the light of existing theories

Statistical study of different solar activity features with total column ozone at two hill stations of Uttarakhand

This paper presents a statistical study of different solar activity features (DSAF) viz., sunspot number (SN), solar active prominences (SAP), solar flares (SF) and solar proton events (SPE) with total column ozone amount using 28 years (1986-2013) data. The ozone data has been taken for two hill stations of Uttarakhand i.e. Nainital (29º 23' N, 79º27' E) and Mussoorie (30° 27' N, 78° 06' E). Graphs are plotted between Total Column Ozone (TCO) and DSAF for months Jan to Dec, annually. We obtained a positive correlation coefficient (r) between TCO and DSAF. The value of r for TCO-Nainital with SN, SAP, SF and SPE is found to be 0.51, 0.30, 0.49, and 0.54 respectively and for TCO-Mussoorie with SN, SAP, SF, SPE is found to be 0.45, 0.27, 0.44, and 0.51.  This supports the fact that solar activity features contribute to the production of ozone

Statistical study of different solar activity features with total column ozone at two hill stations of Uttarakhand

251-262This paper presents a statistical study of different solar activity features (DSAF), viz. sunspot number (SN), solar active prominences (SAP), solar flares (SF) and solar proton events (SPE) with total column ozone (TCO) amount using 28 years (1986-2013) data. The ozone data has been taken for two hill stations of Uttarakhand, viz. Nainital (29º23'N, 79º27'E) and Mussoorie (30°27'N, 78°06'E). The study reveals a positive correlation between yearly averaged TCO and DSAF. The value of linear correlation coefficient (r) for TCO-Nainital with SN, SAP, SF and SPE is found to be 0.51, 0.30, 0.49, and 0.54, respectively and for TCO-Mussoorie with SN, SAP, SF, SPE is found to be 0.45, 0.27, 0.44, and 0.51, respectively. This supports the fact that solar activity features contribute to the production of ozone. Also the trend in TCO over both the stations annually, monthly and seasonally has been studied. A negative trend is observed indicating a decrease in the ozone concentration over these stations in given time period

Evaluation of different diffuse radiation models for Indian stations and predicting the best fit model

In the present study, the non-linear solar radiation models for predicting the monthly average daily diffuse radiation are developed using the measured data on global radiation, diffuse radiation and sunshine hours for 12 locations of India. Statistical method is used to derive these correlations. The developed models are employed to estimate the monthly average daily diffuse radiation. The performance of these correlations is compared with existing model. Accuracy of developed relationships is also tested using statistical indicators viz. Percentage error (PE), root mean square error (RMSE), mean percentage error (MPE) and mean bias error (MBE). The study finds that these statistical parameters have very low values for the proposed models. A cubic correlation of diffuse coefficient with percent possible sunshine gives the best fit. The maximum values of RMSE, MPE and MBE for the proposed third order equation are 4.33%, 8.68% and -1.25% respectively while in the case of existing model these values are 13.28%, 13.39% and -3.83% respectively. Hence, it is possible to apply the cubic equation for the prediction of monthly mean daily diffuse radiation.Percent possible sunshine Empirical models Diffuse fraction Clearness index Parametric model Decomposition model

<span style="font-size:14.0pt;line-height: 115%;font-family:"Times New Roman";mso-fareast-font-family:"Times New Roman"; color:black;mso-ansi-language:EN-IN;mso-fareast-language:EN-IN;mso-bidi-language: HI" lang="EN-IN">Energy transfer between optically excited Dy³⁺ and Er³⁺ ions in zinc phosphate glass</span>

443-446<span style="font-size:14.0pt;line-height: 115%;font-family:" times="" new="" roman";mso-fareast-font-family:"times="" roman";="" color:black;mso-ansi-language:en-in;mso-fareast-language:en-in;mso-bidi-language:="" hi"="" lang="EN-IN">Non-radiative energy transfer from Dy3+ to Er3+ in zinc phosphate glass has been observed at room temperature. The energy transfer mechanism has been found to be mainly electric dipole-dipole in nature. The energy transfer efficiencies, transfer probabilities average donor-acceptor distances and critical transfer distances have been computed.</span