CMEs in the Heliosphere: III. A Statistical Analysis of the Kinematic Properties Derived from Stereoscopic Geometrical Modelling Techniques Applied to CMEs Detected in the Heliosphere from 2008 to 2014 by STEREO/HI-1

AbstractWe present an analysis of coronal mass ejections (CMEs) observed by the Heliospheric Imagers (HIs) onboard NASA’s Solar Terrestrial Relations Observatory (STEREO) spacecraft. Between August 2008 and April 2014 we identify 273 CMEs that are observed simultaneously, by the HIs on both spacecraft. For each CME, we track the observed leading edge, as a function of time, from both vantage points, and apply the Stereoscopic Self-Similar Expansion (SSSE) technique to infer their propagation throughout the inner heliosphere. The technique is unable to accurately locate CMEs when their observed leading edge passes between the spacecraft; however, we are able to successfully apply the technique to 151, most of which occur once the spacecraft-separation angle exceeds $180^{\circ }$ 180 ∘ , during solar maximum. We find that using a small half-width to fit the CME can result in inferred acceleration to unphysically high velocities and that using a larger half-width can fail to accurately locate the CMEs close to the Sun because the method does not account for CME over-expansion in this region. Observed velocities from SSSE are found to agree well with single-spacecraft (SSEF) analysis techniques applied to the same events. CME propagation directions derived from SSSE and SSEF analysis agree poorly because of known limitations present in the latter.

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CMEs in the Heliosphere: II. A Statistical Analysis of the Kinematic Properties Derived from Single-Spacecraft Geometrical Modelling Techniques Applied to CMEs Detected in the Heliosphere from 2007 to 2017 by STEREO/HI-1

Solar Physics ◽

10.1007/s11207-019-1444-4 ◽

2019 ◽

Vol 294 (5) ◽

Cited By ~ 6

Author(s):

D. Barnes ◽

J. A. Davies ◽

R. A. Harrison ◽

J. P. Byrne ◽

C. H. Perry ◽

...

Keyword(s):

Statistical Analysis ◽

Geometrical Modelling ◽

Modelling Techniques ◽

Kinematic Properties

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Ulysses COSPIN observations of cosmic rays and solar energetic particles from the South Pole to the North Pole of the Sun during solar maximum

Annales Geophysicae ◽

10.5194/angeo-21-1217-2003 ◽

2003 ◽

Vol 21 (6) ◽

pp. 1217-1228 ◽

Cited By ~ 56

Author(s):

R. B. McKibben ◽

J. J. Connell ◽

C. Lopate ◽

M. Zhang ◽

J. D. Anglin ◽

...

Keyword(s):

Cosmic Rays ◽

Solar Maximum ◽

Cosmic Ray ◽

Energetic Particles ◽

Solar Energetic Particles ◽

Polar Regions ◽

The Sun ◽

The South ◽

The North ◽

Inner Heliosphere

Abstract. In 2000–2001 Ulysses passed from the south to the north polar regions of the Sun in the inner heliosphere, providing a snapshot of the latitudinal structure of cosmic ray modulation and solar energetic particle populations during a period near solar maximum. Observations from the COSPIN suite of energetic charged particle telescopes show that latitude variations in the cosmic ray intensity in the inner heliosphere are nearly non-existent near solar maximum, whereas small but clear latitude gradients were observed during the similar phase of Ulysses’ orbit near the 1994–95 solar minimum. At proton energies above ~10 MeV and extending up to >70 MeV, the intensities are often dominated by Solar Energetic Particles (SEPs) accelerated near the Sun in association with intense solar flares and large Coronal Mass Ejections (CMEs). At lower energies the particle intensities are almost constantly enhanced above background, most likely as a result of a mix of SEPs and particles accelerated by interplanetary shocks. Simultaneous high-latitude Ulysses and near-Earth observations show that most events that produce large flux increases near Earth also produce flux increases at Ulysses, even at the highest latitudes attained. Particle anisotropies during particle onsets at Ulysses are typically directed outwards from the Sun, suggesting either acceleration extending to high latitudes or efficient cross-field propagation somewhere inside the orbit of Ulysses. Both cosmic ray and SEP observations are consistent with highly efficient transport of energetic charged particles between the equatorial and polar regions and across the mean interplanetary magnetic fields in the inner heliosphere.Key words. Interplanetary physics (cosmic rays) – Solar physics, astrophysics and astronomy (energetic particles; flares and mass ejections)

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Bibliographic Analysis of Operations Research Citation in the Environmental Domain

International Journal of Decision Support System Technology ◽

10.4018/ijdsst.2020040104 ◽

2020 ◽

Vol 12 (2) ◽

pp. 67-79

Author(s):

Peter Keenan

Keyword(s):

Data Envelopment Analysis ◽

Operations Research ◽

Web Of Science ◽

Research Management ◽

Data Envelopment ◽

Bibliographic Analysis ◽

Analysis Techniques ◽

Modelling Techniques ◽

The Web

This article uses bibliographic analysis techniques to examine the papers in the Web of Science database that have citation links to key operations research/management science (OR/MS) journals. The research identified the journals and papers in the environmental domains which cite these OR/MS journals and identify the key journals, papers, and themes. This research shows that environmental disciplines are becoming more important relative to the business and engineering domains that predominated in the previous years. However, much of the citation of OR/MS journals is for techniques like data envelopment analysis (DEA) which are used to conduct research rather than directly model environmental problems. Of the modelling techniques used to address problems in the environmental domains, MCDM methods are the most often cited, reflecting the importance of MCDM with the decision support systems (DSS) field. There are also significant numbers of applications relating to logistics and energy which cite OR/MS papers. Further research is needed to clarify the role of OR/MS techniques in the environmental sector, a domain outside the traditional areas of OR/MS application.

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Combined geometrical modelling and white-light mass determination of coronal mass ejections

Astronomy and Astrophysics ◽

10.1051/0004-6361/201833829 ◽

2019 ◽

Vol 623 ◽

pp. A139 ◽

Cited By ~ 4

Author(s):

Adam Pluta ◽

Niclas Mrotzek ◽

Angelos Vourlidas ◽

Volker Bothmer ◽

Neel Savani

Keyword(s):

Coronal Mass Ejections ◽

Large Scale ◽

Special Focus ◽

Central Meridian ◽

Mass Determination ◽

Geometrical Modelling ◽

Order Of Magnitude ◽

Online Catalogue ◽

Vantage Points

Context. We use forward modelling on multi-viewpoint coronagraph observations to estimate the 3-dimensional morphology, initial speed and deprojected masses of Coronal Mass Ejections (CMEs). The CME structure is described via the Graduated Cylindrical Shell (GCS) model, which enables the measurement of CME parameters in a consistent and comparable manner. Aims. This is the first large-scale use of the GCS model to estimate CME masses, so we discuss inherent peculiarities and implications for the mass determination with a special focus on CME events emerging from close to the observer’s central meridian. Further, we analyse the CME characteristics best suited to estimate the CME mass in a timely manner to make it available to CME arrival predictions. Methods. We apply the method to a set of 122 bright events observed simultaneously from two vantage points with the COR2 coronagraphs onboard of the twin NASA STEREO spacecraft. The events occurred between January 2007 and December 2013 and are compiled in an online catalogue within the EU FP7 project HELCATS. We statistically analyse the derived CME parameters, their mutual connection and their relation to the solar cycle. Results. We show that the derived morphology of intense disk events is still systematically overestimated by up to a factor of 2 with stereoscopic modelling, which is the same order of magnitude as for observations from only one vantage point. The overestimation is very likely a combination of projection effects as well as the increased complexity of separating CME shocks and streamers from CME fronts for such events. We further show that CME mass determination of disk events can lead to overestimation of the mass by about a factor of 10 or more, in case of overlapping bright structures. Conclusions. We conclude that for stereoscopic measurements of disk events, the measurement of the initial CME speed is the most reliable one. We further suggest that our presented CME speed-mass correlation is most suited to estimate the CME mass early from coronagraph observations.

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Gravity currents with residual trapping

Journal of Fluid Mechanics ◽

10.1017/s002211200800219x ◽

2008 ◽

Vol 611 ◽

pp. 35-60 ◽

Cited By ~ 200

Author(s):

M. A. HESSE ◽

F. M. ORR ◽

H. A. TCHELEPI

Keyword(s):

Scaling Law ◽

Leading Edge ◽

Power Laws ◽

Gravity Currents ◽

Sharp Interface Model ◽

Current Volume ◽

Residual Trapping ◽

Self Similar ◽

Loss Term ◽

Structural Closure

Motivated by geological carbon dioxide (CO2) storage, we present a vertical-equilibrium sharp-interface model for the migration of immiscible gravity currents with constant residual trapping in a two-dimensional confined aquifer. The residual acts as a loss term that reduces the current volume continuously. In the limit of a horizontal aquifer, the interface shape is self-similar at early and at late times. The spreading of the current and the decay of its volume are governed by power-laws. At early times the exponent of the scaling law is independent of the residual, but at late times it decreases with increasing loss. Owing to the self-similar nature of the current the volume does not become zero, and the current continues to spread. In the hyperbolic limit, the leading edge of the current is given by a rarefaction and the trailing edge by a shock. In the presence of residual trapping, the current volume is reduced to zero in finite time. Expressions for the up-dip migration distance and the final migration time are obtained. Comparison with numerical results shows that the hyperbolic limit is a good approximation for currents with large mobility ratios even far from the hyperbolic limit. In gently sloping aquifers, the current evolution is divided into an initial near-parabolic stage, with power-law decrease of volume, and a later near-hyperbolic stage, characterized by a rapid decay of the plume volume. Our results suggest that the efficient residual trapping in dipping aquifers may allow CO2 storage in aquifers lacking structural closure, if CO2 is injected far enough from the outcrop of the aquifer.

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Inviscid hypersonic flow on cusped concave surfaces

Journal of Fluid Mechanics ◽

10.1017/s0022112066000533 ◽

1966 ◽

Vol 24 (1) ◽

pp. 99-112 ◽

Cited By ~ 6

Author(s):

Philip A. Sullivan

Keyword(s):

Shock Wave ◽

Surface Pressure ◽

Leading Edge ◽

Pressure Change ◽

Inviscid Flow ◽

Small Region ◽

The Body ◽

Cubic Surface ◽

Self Similar ◽

Modelling cosmic ray intensities along the Ulysses trajectory

Annales Geophysicae ◽

10.5194/angeo-23-1061-2005 ◽

2005 ◽

Vol 23 (3) ◽

pp. 1061-1070 ◽

Cited By ~ 36

Author(s):

D. C. Ndiitwani ◽

S. E. S. Ferreira ◽

M. S. Potgieter ◽

B. Heber

Keyword(s):

Transport Model ◽

Solar Maximum ◽

Cosmic Ray ◽

Time Dependent ◽

Global Changes ◽

Cosmic Ray Modulation ◽

Magnetic Field Magnitude ◽

Additional Reduction ◽

Charge Sign ◽

Inner Heliosphere

Abstract. Time dependent cosmic ray modulation in the inner heliosphere is studied by comparing results from a 2-D, time-dependent cosmic ray transport model with Ulysses observations. A compound approach, which combines the effects of the global changes in the heliospheric magnetic field magnitude with drifts to establish a realistic time-dependence, in the diffusion and drift coefficients, are used. We show that this model results in realistic cosmic ray modulation from the Ulysses launch (1990) until recently (2004) when compared to 2.5-GV electron and proton and 1.2-GV electron and Helium observations from this spacecraft. This approach is also applied to compute radial gradients present in 2.5-GV cosmic ray electron and protons in the inner heliosphere. The observed latitude dependence for both positive and negative charged particles during both the fast latitude scan periods, corresponding to different solar activity conditions, could also be realistically computed. For this an additional reduction in particle drifts (compared to diffusion) toward solar maximum is needed. This results in a realistic charge-sign dependent modulation at solar maximum and the model is also applied to predict charge-sign dependent modulation up to the next expected solar minimum.

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