Three-dimensional Evolution of Solar Wind during Solar Cycles 22-24

This paper presents the analysis of 3D evolution of solar wind density turbulence and speed at various levels of solar activity between solar cycles 22 and 24. The solar wind data has been obtained from interplanetary scintillation (IPS) measurements made at the Ooty Radio Telescope. Results show that (i) on the average, there was a downward trend in density turbulence from the maximum of cycle 22 to the deep minimum phase of cycle 23; (2) the scattering diameter of the corona around the Sun shrunk steadily towards the Sun, starting from 2003 to the smallest size at the deepest minimum, and it corresponded to a reduction of ~50% in density turbulence between maximum and minimum phases of cycle 23; (3) The latitudinal distribution of solar wind speed was significantly different between minima of cycles 22 and 23. At the minimum phase of solar cycle 22, when the underlying solar magnetic field was simple and nearly dipole in nature, the high-speed streams were observed from poles to ~30 deg. latitudes in both hemispheres. In contrast, in the long-decay phase of cycle 23, the sources of high-speed wind at both poles, in accordance with the weak polar fields, occupied narrow latitude belts from poles to ~60 deg. latitudes. Moreover, in agreement with the large amplitude of heliospheric current sheet, the low-speed wind prevailed the low- and mid-latitude regions of the heliosphere. (4) At the transition phase between cycles 23 and 24, the high levels of density and density turbulence were observed close to the heliospheric equator and the low-speed speed wind extended from equatorial- to mid-latitude regions. Results are consistent with the onset of the current cycle 24, from middle of 2009 and it has almost reached near to the maximum phase at the northern hemisphere of the Sun, but activity not yet developed in the southern hemisphere.Comment: 14 pages, 9 figures, Accepted for Publication in The Astrophysical Journa

Solar cycle changes of large-scale solar wind structure

In this paper, I present the results on large-scale evolution of density turbulence of solar wind in the inner heliosphere during 1985 - 2009. At a given distance from the Sun, the density turbulence is maximum around the maximum phase of the solar cycle and it reduces to ~70%, near the minimum phase. However, in the current minimum of solar activity, the level of turbulence has gradually decreased, starting from the year 2005, to the present level of ~30%. These results suggest that the source of solar wind changes globally, with the important implication that the supply of mass and energy from the Sun to the interplanetary space has significantly reduced in the present low level of activity.Comment: 3 pages, 2 figure

Coronal Mass Ejections - Propagation Time and Associated Internal Energy

In this paper, we analyze 91 coronal mass ejection (CME) events studied by Manoharan et al. (2004) and Gopalswamy and Xie (2008). These earth-directed CMEs are large (width $>$160$^\circ$) and cover a wide range of speeds ($\sim$120--2400 {\kmps}) in the LASCO field of view. This set of events also includes interacting CMEs and some of them take longer time to reach 1 AU than the travel time inferred from their speeds at 1 AU. We study the link between the travel time of the CME to 1 AU (combined with its final speed at the Earth) and the effective acceleration in the Sun-Earth distance. Results indicate that (1) for almost all the events (85 out of 91 events), the speed of the CME at 1 AU is always less than or equal to its initial speed measured at the near-Sun region, (2) the distributions of initial speeds, CME-driven shock and CME speeds at 1 AU clearly show the effects of aero-dynamical drag between the CME and the solar wind and in consequence, the speed of the CME tends to equalize to that of the background solar wind, (3) for a large fraction of CMEs (for $\sim$50% of the events), the inferred effective acceleration along the Sun-Earth line dominates the above drag force. The net acceleration suggests an average dissipation of energy $\sim$10$^{31-32}$ ergs, which is likely provided by the Lorentz force associated with the internal magnetic energy carried by the CME.Comment: 18 pages, 6 figure

Evolution of Solar Magnetic Field and Associated Multi-wavelength Phenomena: Flare events on 20 November 2003

We analyze H-alpha images, soft X-ray profiles, magnetograms, extreme ultra-violet images and radio observations of two homologous flare events (M1.4/1N and M9.6/2B) on 20 November 2003 in the active region NOAA 10501 and study properties of reconnection between twisted filament systems, energy release and associated launch of coronal mass ejections (CMEs). During both events twisted filaments observed in H-alpha approached each other and initiated the flare processes. However, the second event showed the formation of cusp as the filaments interacted. The rotation of sunspots of opposite polarities, inferred from magnetograms likely powered the twisted filaments and injection of helicity. Along the current sheet between these two opposite polarity sunspots, the shear was maximum, which could have caused the twist in the filament. At the time of interaction between filaments, the reconnection took place and flare emission in thermal and non-thermal energy ranges attained the maximum. The radio signatures revealed the opening of field lines resulting from reconnection. The H-alpha images and radio data provide the inflow speed leading to reconnection and the scale size of particle acceleration region. The first event produced a narrow and slow CME, whereas the later one was associated with a fast full halo CME. The halo CME signatures observed between Sun and Earth using white-light and scintillation images and in-situ measurements indicated the magnetic energy utilized in the expansion and propagation. The magnetic cloud signature at the Earth confirmed the flux rope ejected at the time of filament interaction and reconnection.Comment: 22 pages, 16 figures, Accepted for the publication in Astrophysical Journal (APJ

Optimisation of supply chain management in Spotless Catering

Global warming is a reality. Organisations realise their corporate responsibility to conduct their business with the 'future' in mind. Sustainability is having a green conscience and ensuring the steps you take today do not have a negative impact on the future. Green Human Resources Management is to promote the sustainable use of resources within business organisations. The aim of this research is to provide organisations with a Green Human Resource Management Strategy (GHRM). A qualitative approach was followed, and five participants interviewed. The researcher followed this approach to gain an in-depth understanding of business eco-friendly practices, to ascertain if they utilise HR to drive “green” in the organisation and engage employees. The study found that most organisations have implemented some eco-friendly practice and know the value of becoming a 'green' employer. However, the researcher identified a significant gap in that organisations are not aware of or lack the knowledge of how to utilise HR practices to get staff engaged in green policies and procedures. The researcher will strive to come up with various ideas and recommendation to the business on how they can utilise their HR practices to go green and engage their staff

Ideal Graph of a Graph

In this paper, we introduce ideal graph of a graph and study some of its properties. We characterize connectedness, isomorphism of graphs and coloring property of a graph using ideal graph. Also, we give an upper bound for chromatic number of a graph