A FAST ALGORITHM FOR CALCULATION OF RADIATIVE ENERGY DISTRIBUTIONS RECEIVED BY PINHOLE IMAGE-FORMATION PROCESS FROM 2D RECTANGULAR ENCLOSURES

2000 ◽  
Vol 38 (7) ◽  
pp. 757-773 ◽  
Author(s):  
Huai-Chun Zhou, Feng Sheng, Shu-Don
Keyword(s):  
Formation Process ◽  
Fast Algorithm ◽  
Image Formation ◽  
Radiative Energy ◽  
Energy Distributions ◽  
Pinhole Image

scholarly journals Power-law energy distributions of small-scale impulsive events on the active Sun: results from IRIS

2020 ◽  
Vol 499 (1) ◽  
pp. 1385-1394
Author(s):  
Nived Vilangot Nhalil ◽  
Chris J Nelson ◽  
Mihalis Mathioudakis ◽  
J Gerry Doyle ◽  
Gavin Ramsay
Keyword(s):  
Energy Range ◽  
Power Law ◽  
Coronal Heating ◽  
Radiative Energy ◽  
Small Scale ◽  
Data Sets ◽  
Imaging Data ◽  
Power Law Distribution ◽  
Energy Distributions ◽  
Power Law Index

ABSTRACT Numerous studies have analysed inferred power-law distributions between frequency and energy of impulsive events in the outer solar atmosphere in an attempt to understand the predominant energy supply mechanism in the corona. Here, we apply a burst detection algorithm to high-resolution imaging data obtained by the Interface Region Imaging Spectrograph to further investigate the derived power-law index, γ, of bright impulsive events in the transition region. Applying the algorithm with a constant minimum event lifetime (of either 60 s or 110 s) indicated that the target under investigation, such as Plage and Sunspot, has an influence on the observed power-law index. For regions dominated by sunspots, we always find γ < 2; however, for data sets where the target is a plage region, we often find that γ > 2 in the energy range (∼1023, ∼1026) erg. Applying the algorithm with a minimum event lifetime of three time-steps indicated that cadence was another important factor, with the highest cadence data sets returning γ > 2 values. The estimated total radiative power obtained for the observed energy distributions is typically 10–25 per cent of what would be required to sustain the corona indicating that impulsive events in this energy range are not sufficient to solve coronal heating. If we were to extend the power-law distribution down to an energy of 1021 erg, and assume parity between radiative energy release and the deposition of thermal energy, then such bursts could provide 25–50 per cent of the required energy to account for the coronal heating problem.

scholarly journals Binaries in Globular Clusters

1998 ◽  
Vol 11 (2) ◽  
pp. 616-621 ◽  
Author(s):  
S. L. W. Mcmillan ◽  
C. Pryor ◽  
E. S. Phinney
Keyword(s):  
Kinetic Energy ◽  
Globular Cluster ◽  
Binary Stars ◽  
Formation Process ◽  
Globular Clusters ◽  
The Other ◽  
Energy Distributions ◽  
Other Hand ◽  
Mass Segregation ◽  
Three Body

Binary stars in a globular cluster (hereafter, GC) may be primordial (i.e. formed along with the cluster), or the result of cluster dynamics. “Dynamical” binaries can result from conservative three-body encounters (e.g. Spitzer, 1987) if a third star can carry away enough kinetic energy to leave two others bound, or from dissipative two-body encounters, if two stars happen to pass within a few stellar radii of one other (Fabian, Pringle, & Rees, 1975). Such non-primordial systems are likely to be found primarily in evolved GC cores, both because conditions are more favorable for making them there, and because of mass segregation. Knowledge of the formation process allows reasonable estimates to be made of their mass and energy distributions. The initial spatial, mass, and energy distributions of primordial binaries, on the other hand, are largely unknown.

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