Yatendra Pal Singh
Verified @mangalayatan.edu.in
Director IQAC
Mangalayatan University
RESEARCH INTERESTS
Solar Physics
Scopus Publications
Scholar Citations
Scholar h-index
Scholar i10-index
Scopus Publications
P R Singh, A I Saad Farid, Y P Singh, A K Singh, and Ayman A Aly
IOP Publishing
Abstract To study the solar rotational oscillation on daily averaged time series of solar activity proxies: sunspot number (SSN), modified coronal index (MCI), solar flare index (FI), and cosmic ray intensity (CRI) are subjected to Lomb/Scargle periodogram, and continuous wavelet transform. For this purpose, we have used data of all the considered parameters from 2012 to 2015, which covers the maximum phase including the polarity reversal period of the solar cycle 24. Both spectral analysis techniques are carried out to study the behavior of 27-days on the time scale of the synodic period and to follow their evolution throughout the epoch. Further, we have used R package RobPer (least square regression) techniques and obtained a significant true period ∼27 days is present in this study. It is noted that the ∼27-day period of solar activity parameters and cosmic rays is much prominent during the examined period.
Y. P. Singh
American Geophysical Union (AGU)
Y. P. Singh and Badruddin
Springer Science and Business Media LLC
Significant short-term variations of ≈1.7, ≈2.4, ≈2.8, ≈3.3, ≈3.8 days periods are found when high resolution data (five minutes average) of interplanetary electric field (Ey), south ward component of magnetic field (Bz) and geomagnetic index (AE) is subjected to wavelet analysis. The fourth, fifth, sixth sub harmonics of ≈27-day period, and few other short-term periods are significantly reported by Singh and Badruddin (Astrophys. Space Sci. 359:60, 2015a; Solar Phys. 290:3071, 2015b and Solar Phys. 294:27, 2019) in cosmic ray intensity, geomagnetic activity index and various solar wind plasma and field parameters. The reported and observed periods ≈6.8 day, ≈5.5 day, ≈4.4 day, ≈3.9 day, ≈3.4 day, ≈3.0 day, ≈2.8 day, ≈2.4 day, ≈2.2 day, ≈2.0 day, ≈1.9 day, ≈1.8 day; and ≈1.7 day are close to integral multiples of 1/4, 1/5, 1/6, 1/7, 1/8, 1/9, 1/10, 1/11, 1/12, 1/13, 1/14, 1/15 and 1/16 of one solar rotation period (≈27.0 day), hence these periods could be sub harmonics of fundamental period (≈27 day). If so, then these results lead to infer some sort of continuous simultaneous oscillations of active regions having integral multiple frequencies and varying amplitudes occurring on the solar disc.
Y. P. Singh and Badruddin
Springer Science and Business Media LLC
Short-term variations of interplanetary magnetic field, solar wind speed, solar radio flux, geomagnetic ap index and cosmic ray intensity have been studied during the last five polarity reversal periods in the period from Solar Cycles 20 to 24. Hourly data of all the considered parameters are subject to wavelet analysis exclusively during the polarity reversal periods of these five solar cycles. These solar polarity reversal periods lie during or around the solar maximum of the respective solar cycles. Study reveals a few noteworthy results during these disturbed periods. Periodicities such as the synodic period (≈27.0${\\approx\\,}27.0$ days), its second (≈13.5${\\approx\\,}13.5$ days) and third (≈9.1${\\approx\\,}9.1$-days) harmonics, ≈6.8${\\approx\\,}6.8$-day, ≈5.5${\\approx\\,}5.5$-day and ≈4.2${\\approx\\,}4.2$-day periods are consistently observed during the reversal times with prominent signatures in addition to quasi-periodicities (18.5 days, 16.7 days, 10.6 days, 2.8 days, 2.4 days, and 1.8 days). These significant variations are very strong during reversal periods as they appear in minimum phases of the solar cycles, as reported by Singh and Badruddin (Astrophys. Space Sci.359, 60, 2015a); they could be the higher harmonics (fourth, fifth, and sixth) of the synodic period.
Y.P. Singh and Badruddin
Elsevier BV
Abstract Short-and mid-term oscillations of the solar activity (sunspot number and 10.7 cm solar flux), geomagnetic activity (Ap index) and cosmic-ray intensity (neutron monitor count rate) are analysed during the past two solar-magnetic cycles (1968–1989 and 1989–2014). We have implemented the wavelet analysis on the daily time resolution data of sunspot number (SSN), 10.7 cm solar flux, geomagnetic Ap index and Oulu neutron monitor count rate. Results suggest that few quasi and intermittent oscillations are observed with remarkable power density in addition to fundamental periods, like 27 day (synodic period), 154 day (Rieger period), semi-annual, annual, 1.3 year, and 1.7 year. We have consistently observed first (27 day), second (13.5 day) and third (9.0 day) solar-rotation harmonics in the geomagnetic Ap-index during both the magnetic cycles. Rieger period is more pronounced in SSN and solar flux during 1980-82 and 1990-92. Semi-annual variation of Ap-index is consistently observed during both the magnetic cycles. The annual and ~1.85 year variation are also observed in all the considered parameters with good signatures in CRI.
Y. P. Singh and Badruddin
Springer Science and Business Media LLC
The behavior of short-term oscillations (≤one solar rotation) of the solar-wind parameters, galactic cosmic rays and geomagnetic indices are discussed during the last two solar minima between cycles 22/23$22/23$ and cycles 23/24$23/24$. There are strong signatures of short-term oscillations of all the selected time series during the early phase of the minima, where the high speed streams are prominent structures in the heliosphere and these signatures almost die out at the end of the two minima. Result also suggests that the second and third harmonics of one solar rotation period of few parameters are prominent during the minimum between the cycles 22 and 23. Moreover, all the sub-harmonics/quasi-oscillations are more consistent and deviate less during the recent deep prolonged minimum. Through this work, we are reporting ∼7.1 days, ∼5.5 days, ∼4.4 days, ∼3.3 days oscillations, observed in few solar-wind parameters [interplanetary magnetic field (B)$(B)$, RMS standard deviation in the magnetic field (σB$\\sigma_{B}$), southward component of magnetic field (Bz)$(\\mathit{Bz})$ and electric field (Ey)$(\\mathit{Ey})$] and geomagnetic (DsT$D_{\\mathit{sT}}$ and AE$\\mathit{AE}$) parameters during the solar minimum between cycles 23 and 24, in addition to ∼1.9 days oscillations which is observed in Bz$\\mathit{Bz}$, Ey$\\mathit{Ey}$ and AE$\\mathit{AE}$ parameters.
Y. P. Singh and Badruddin
Springer Science and Business Media LLC
The recent, unusual solar cycle and solar minima between Cycles 23 and 24 have been studied extensively. Wavelet analysis of hourly cosmic-ray intensity during the last five solar minima reveals a number of short-term variations with few temporal shifts in the periods. This study suggests that deviations with a one-solar-rotation period and its harmonics are small during the recent minimum. However, deviations are considerably larger during the other minima. Analysis also demonstrates that the behavior of active regions is nearly the same during the minima of Cycles 19, 20, 21, and 22. The results also suggest that regions outside the streamer stalk are significantly larger in the recent solar minimum as opposed to the other minima.
Saurabh Mukerji, Ahmad Khan, and Yatendra Singh
CRC Press
Y.P. Singh and Badruddin
Elsevier BV
Abstract Study of periodicities in solar and geomagnetic parameters has been useful in relating solar variability to variations in other phenomena in order to search for the solar cause of, and effects in, the variability observed in near earth space environment. Implementing wavelet analysis on daily, monthly and yearly time resolution data of sunspot number and geomagnetic aa-index, we observed periodicities of 27.8-, 157-, 370-days, and 2.2-, 5.5-, 11-, 22.7-, 38.6-years in the sunspot spot number and 13.8-, 26.6-, 185-days, and 5.3-, 11-, 30-, 46-years in the geomagnetic aa-index. We discuss these periodicities, relation between solar and geomagnetic periodicities and their implications for near-earth space environmental effects.
Y.P. Singh, Shweta Gautam, and Badruddin
Elsevier BV
Abstract Galactic cosmic rays entering the heliosphere are modulated by solar wind plasma and the associated magnetic field. Solar wind parameters (solar wind speed, plasma density and interplanetary magnetic field) and galactic cosmic ray intensity during solar cycle 23 have been analyzed using wavelet analysis. The global wavelet spectrum of these parameters shows the existence of a variety of prominent short- and mid-term periodicities. The well known one-solar rotation (∼27 days) periodicity is observed in all the considered parameters, while few fluctuations less than one-solar rotation (∼9 and ∼14 days) are observed only in solar parameters. Annual, semi-annual and tri-annual variations are found in the interplanetary magnetic field and a periodicity of ∼200 days is observed in plasma speed and density. Few additional mid-term periodicities, ∼99 days and ∼1.7 years in plasma speed, ∼75 days and ∼1.4 years in plasma density are also observed. In cosmic ray data, in addition to one solar rotation (∼27 days) periodicity, we observed ∼66 days, ∼140 days, ∼260 days and ∼1.3 years periodicities. Our results also show that the temporal behaviors of short-term periodicities of these parameters are almost uniform throughout the cycle length while it is quite different in variations as well as in amplitudes for mid-term fluctuations.
Y.P. Singh and Badruddin
Elsevier BV
Abstract We have identified and selected 212 geomagnetic disturbances of varying level of geomagnetic activity, based on the changes in Dst index. The selected events are divided into six different groups according to different geomagnetic activity levels. We study the average behavior of solar plasma flow speed (V), density (N), dynamic pressure (P), magnetic field (B), its north–south component (Bz) and variance (σB) and dusk-ward electric field (Ey), and their role in solar wind–magnetosphere coupling. For this purpose we adopted the method of superposed epoch (SPE) analysis. Hourly solar wind plasma and field parameters (V, B, Bz, σB, N, P, Ey) together with Dst index are analyzed using SPE analysis with respect to the start of the changes in geomagnetic activity, separately for all six groups of increasing level of activity. In particular, we study the influence of the enhancements in solar plasma density/dynamic pressure and field fluctuations on the solar wind–magnetosphere coupling, during southward field orientation within the responsible interplanetary structures. In addition to studying the average properties with the use of SPE analysis, we have also considered individual events with different level of geomagnetic activity (Dst) and studied its relationship to interplanetary field parameters. We observed that the enhancement in plasma density/pressure and fluctuations in field starting several hours before the storm/activity onset, might play a role in enhancing the solar wind–magnetosphere coupling efficiency.
Saurabh Kumar Mukerji, Daya Shanker Srivastava, Yatendra Pal Singh, and Dharam Veer Avasthi
The Electromagnetics Academy
The distribution of flelds travelling in the laminated structure with assumed values for the tangential components of the magnetic fleld intensities on the top and bottom surfaces of the structure, has been obtained using linear electromagnetic fleld theory. The treatment takes cognizance of interlaminar capacitance inherently present in a laminated structure. Analysis presented in this paper assumes identical fleld distribution in each lamination. It has been concluded that convection currents are developed at the interface between iron and insulator regions.
Badruddin and Y.P. Singh
Elsevier BV
Abstract A subset of CMEs, called interplanetary magnetic clouds (MCs), are observed to have systematic rotation [northward to southward (NS) or southward to northward (SN)] in their field structures. These MCs identified in the heliospheric plasma and field data at 1 AU may have different features associated with them. These structures (NS/SN) may be isolated MC moving with the ambient solar wind. MCs (NS/SN) may also be associated with shock/sheath region, formed due to compression of the ambient plasma/field ahead of them. A fraction from each of these four types of MCs have additional features, being ‘pushed’ by fast solar wind streams from coronal holes, forming interaction region (IR) between MCs and high-speed solar wind streams (HSS). Using these different sets of MCs, we have done a detailed study of the geoeffectiveness of NS and SN turning MCs and their associated features (shock/sheath, IR and HSS). To study the process that produces the geomagnetic disturbances and influences its amplitude/duration, we have utilized the interplanetary plasma and field parameters, namely, plasma velocity, density, temperature, pressure, field strength and its north–south component, during the passage of these structures with different associated properties. Differences in the geoeffectiveness of MCs with different structural and dynamical properties have been identified. The possible role of high-speed stream in influencing the recovery time (and hence duration) of geomagnetic disturbance has also been investigated. A best-fit equation representing the relation between level of the geomagnetic activity (due to MCs) and interplanetary plasma/field parameter has been obtained.
M. Singh, Y.P. Singh, and Badruddin
Elsevier BV
Abstract We study the cosmic ray modulation during different solar cycles and polarity states of the heliosphere. We determine (a) time lag between the cosmic ray intensity and the solar variability, (b) area of the cosmic ray intensity versus solar activity modulation loops and (c) dependence of the cosmic ray intensity on the solar variability, during different solar activity cycles and polarity states of the heliosphere. We find differences during odd and even solar cycles. Differences during positive and negative polarity periods are also found. Consequences and implications of the observed differences during (i) odd and even cycles, and (ii) opposite polarity states ( A A >0) are discussed in the light of the modulation models, including drift effects.
Y. P. Singh and Badruddin
American Geophysical Union (AGU)
[1] We studied the solar magnetic cycle dependence of cosmic ray depressions due to the corotating high-speed solar wind streams (CSWS) during different polarity states of the heliosphere. The daily averaged cosmic ray intensity data from Climax, Oulu, and Thule neutron monitors together with simultaneous solar wind plasma and field data were subjected to the superposed epoch analysis with respect to CSWS start time. These analyses were carried out separately in different polarity states of the heliosphere A 0 during solar minimum as well as during the periods of variable solar activity. Although the average variations in the solar wind velocity, IMF strength, and its variance are almost similar, the amplitudes of CSWS-associated cosmic ray depressions are quite different during different polarity epochs; they are larger during A > 0 than A 0 and A 0 than A < 0. Two other solar wind parameters, IMF strength and its variance, do not show a significant relationship with cosmic ray intensity change through the passage of these streams, although the initial depression coincides the enhancement of the two parameters. These results are discussed in the light of existing models of galactic cosmic ray modulation.
Badruddin, M. Singh, and Y. P. Singh
EDP Sciences
Aims. We study certain aspects of the solar modulation of galactic cosmic ray intensity during different solar activity cycles and in different polarity states of the heliosphere. Methods. We plotted modulation loops between the cosmic ray intensity and the tilt angle of the heliospheric current sheet during three solar activity cycles 21, 22 and 23 and obtained the area of modulation loops. The time lag between the tilt angle and the cosmic ray intensity in odd, even solar activity cycles and during $A >$ 0, $A Results. Marked differences during the two odd and the one even solar cycles, as well as during different polarity states of the solar magnetic field ($A >$ 0 and $A $ 0 and $A $ 0, indicating stronger response to the tilt angle changes during $A <$ 0. These results are discussed in the light of 3D modulation models including the gradient and curvature drifts and the tilt of the heliospheric current sheet.
Y. P. Singh and Badruddin
American Geophysical Union (AGU)
[1] Interplanetary manifestations of coronal mass ejections (CMEs) with specific plasma and field properties, called “interplanetary magnetic clouds,” have been observed in the heliosphere since the mid-1960s. Depending on their associated features, a set of observed magnetic clouds identified at 1 AU were grouped in four different classes using data over 4 decades: (1) interplanetary magnetic clouds moving with the ambient solar wind (MC structure), (2) magnetic clouds moving faster than the ambient solar wind and forming a shock/sheath structure of compressed plasma and field ahead of it (SMC structure), (3) magnetic clouds “pushed” by the high-speed streams from behind, forming an interaction region between the two (MIH structure), and (4) shock-associated magnetic clouds followed by high-speed streams (SMH structure). This classification into different groups led us to study the role, effect, and the relative importance of (1) closed field magnetic cloud structure with low field variance, (2) interplanetary shock and magnetically turbulent sheath region, (3) interaction region with large field variance, and (4) the high-speed solar wind stream coming from the open field regions, in modulating the galactic cosmic rays (GCRs). MC structures are responsible for transient decrease with fast recovery. SMC structures are responsible for fast decrease and slow recovery, MIH structures produce depression with slow decrease and slow recovery, and SMH structures are responsible for fast decrease with very slow recovery. Simultaneous variations of GCR intensity, solar plasma velocity, interplanetary magnetic field strength, and its variance led us to study the relative effectiveness of different structures as well as interplanetary plasma/field parameters. Possible role of the magnetic field, its topology, field turbulence, and the high-speed streams in influencing the amplitude and time profile of resulting decreases in GCR intensity have also been discussed.
Y. P. Singh and Badruddin
Springer Science and Business Media LLC
AbstractForbush decrease (FD) events recorded at the ground-based neutron monitors (NMs) during the period 1961 – 1999, have been selected and recovery characteristic of these events have been analyzed. The average profile of FDs observed during different polarity states of the heliosphere is obtained by superposed epoch analysis separately for the periods 1961 – 1969
(A < 0), 1971 – 1979 (A > 0), 1981 – 1989 (A < 0) and 1991 – 1999 (A > 0). Hourly count rate of neutron monitors of different cut-off rigidities have been utilized. The results are compared with model predictions including drifts. No marked difference is observed in the amplitudes of FDs during A < 0 and A > 0. Rigidity spectrum fitted with a power law yields the values of spectral exponent that are closer to values predicted by two-dimensional models including drifts. The recovery rate of FDs varies with the polarity of HMF and the rate is higher (recovery time smaller) during A > 0 than during A < 0 epoch, consistent with the model predictions including the drift effects in the HMF. This difference in recovery time of FDs during A > 0 and A < 0 polarity conditions provides experimental evidence that drift plays an important role in cosmic ray modulation.
Y.P. Singh and Badruddin
Elsevier BV
Abstract Superposed epoch analysis is often used to demonstrate an effect or a periodicity. This method of analysis was originally proposed by Chree (Some phenomena of sunspots and of terrestrial magnetism at Kew observatory. Philosophical Transactions Royal Society London Series A 212, 75) and applied for studying the time variation of geophysical data. In its first application, Chree reported a 27-day periodicity (recurrence tendency) in geomagnetic data. Since then this method of analysis is being used in several disciplines either for testing the relationship between two diverse phenomena or to search for periodicities in the data. In addition to cosmic ray physics, various fields of research in which this method of analysis is often used include solar, magnetospheric, heliospheric, ionospheric and atmospheric physics as well as astrophysics and meteorology/climatology etc. Although a powerful method, an appropriate procedure to test the level of significance (statistical reality) of the obtained results is still lacking. This is highly desirable as, in the absence of a suitable test, a spurious/undesirable signal may appear as a ‘genuine’ effect. This paper describes two techniques with application, one based on t-test and other on F-test, to test the significance level of results obtained on the basis of superposed epoch (Chree) analysis. Since most of the data acquired in atmosphere and space show a solar cycle variation, an appropriate procedure is also described for the data transformation (removal of solar cycle variation) before subjected to test a ‘genuine’ effect. To highlight the necessity for removal of solar cycle effect, a comparison of the results of significance test, before and after the data transformation, is also presented. Although these techniques are applicable to solar/astrophysical/heliospheric/magnetospheric/ionospheric/atmospheric/meteorological data, the procedure is illustrated using cosmic ray data. Details of the procedure to test the Forbush-decrease effect in cosmic ray intensity observed due to passage of interplanetary shocks, are discussed. Test results by two statistical procedures, one based on t -test and another based on F -test, are also compared in this paper. The effectiveness of interplanetary shocks on transient modulation of cosmic rays is studied and tested by both techniques. Both the techniques lead to similar conclusions. It is demonstrated, using both the techniques, that the effect of interplanetary shocks on transient modulation of cosmic ray intensity is statistically significant only due to the shocks whose sudden commencement amplitude exceeds certain limits.
Yatendra Pal Singh, Munendra Singh, and Badruddin
Springer Science and Business Media LLC
The problem of solar wind-magnetosphere coupling is investigated for intense geomagnetic storms (Dst < -100nT) that occurred during solar cycle 23. For this purpose interplanetary plasma and field data during some intensely geo-effective transient solar/interplanetary disturbances have been analysed. A geomagnetic index that represents the intensity of planetary magnetic activity at subauroral latitude and the other that measures the ring current magnetic field, together with solar plasma and field parameters (V, B, Bz, σB, N, and T) and their various derivatives (BV,-BVz, BV2, -BzV2, B2V, Bz2V, NV2) have been analysed in an attempt to study mechanism and the cause of geo-effectiveness of interplanetary manifestations of transient solar events. Several functions of solar wind plasma and field parameters are tested for their ability to predict the magnitude of geomagnetic storm.