scholarly journals A new perspective and explanation for the formation of plasmaspheric shoulder structures

2021 ◽  
Vol 39 (4) ◽  
pp. 701-707
Author(s):  
Hua Zhang ◽  
Guangshuai Peng ◽  
Chao Shen ◽  
Yewen Wu
Keyword(s):  
Electric Field Intensity ◽  
Extreme Ultraviolet ◽  
Particle Model ◽  
Sharp Reduction ◽  
Active Time ◽  
Drift Motion ◽  
Image Satellite ◽  
Time Period ◽  
The Hours ◽  
New Perspective

Abstract. Over the hours of 05:00–09:00 UT on 8 June 2001, the extreme ultraviolet (EUV) instrument on board the IMAGE satellite observed a shoulder-like formation in the morning sector and a post-noon plume-like structure. The plasmapause formation is simulated using the test particle model (TPM), based on a drift motion theory, which reproduces various plasmapause structures and evolution of the shoulder feature. The analysis indicates that the shoulder is created by sharp reduction and spatial non-uniformity in the dawn–dusk convection electric field intensity. The TPM-modeled event is found to develop an initial pre-dawn asymmetric bulge that becomes a shoulder as a result of increased “corotation” rate with an increasing L-shell that is preceded by localized outward convection. The shoulder structure rotates sunward and develops into a single- or double-plume structure during an active time period in simulation.

scholarly journals A New Perspective and Explanation to the Formation of Plasmaspheric Shoulder Structure

2020 ◽  
Author(s):  
Hua Zhang ◽  
Guangshuai Peng ◽  
Chao Shen
Keyword(s):  
Extreme Ultraviolet ◽  
Particle Model ◽  
Sharp Reduction ◽  
Subsequent Evolution ◽  
Drift Motion ◽  
Image Satellite ◽  
The Hours ◽  
Speed Up ◽  
New Perspective ◽  
Radial Outflow

Abstract. Over the hours of 5–9 UT on June 8 2001, the extreme ultraviolet (EUV) instrument onboard IMAGE satellite observed a Shoulder-like formation in the morning sector and a Plume-like structure straddling in the between noon and dusk region. Simulation results of the plasmapause formation based on mechanism of drift motion called Test Particle Model (TPM) and have reproduced various plasmapause structures and subsequent evolution of the Shoulder. The analysis indicated that the Shoulder is created by a dawn-dusk convection electric field intensity, sharp reduction and spatial nonuniform manifested. As, combination of the plasmaspheric rotation rate speed up with L-shell increase and plasma flux do radial outflow in the predawn sector to interact, and produce an asymmetric bulge that rotates eastward. The Shoulder-like structure rotates sunward and develops to the single or double Plume structure during active times.

scholarly journals Cooling of Electrons in a Weakly Outgassing Comet

2020 ◽  
Author(s):  
Peter Stephenson ◽  
Marina Galand ◽  
Jan Deca ◽  
Pierre Henri ◽  
Gianluca Carnielli
Keyword(s):  
Solar Wind ◽  
Extreme Ultraviolet ◽  
Pure Water ◽  
Particle Model ◽  
Particle In Cell ◽  
Electron Sources ◽  
Cometary Plasma ◽  
Impedance Probe ◽  
Cold Electrons ◽  
The Impact

<p>The plasma instruments, Mutual Impedance Probe (MIP) and Langmuir Probe (LAP), part of the Rosetta Plasma Consortium (RPC), onboard the Rosetta mission to comet 67P revealed a population of cold electrons (<1eV) (Engelhardt et al., 2018; Wattieaux et al, 2020; Gilet et al., 2020). This population is primarily generated by cooling warm (~10eV) newly-born cometary electrons through collisions with the neutral coma. What is surprising is that the cold electrons were detected throughout the escort phase, even at very low outgassing rates (Q<1e26 s<sup>-1</sup>) at large heliocentric distances (>3 AU), when the coma was not thought to be dense enough to cool the electron population significantly.</p> <p> Using a collisional test particle model, we examine the behaviour of electrons in the coma of a weakly outgassing comet and the formation of a cold population through electron-neutral collisions. The model incorporates three electron sources: the solar wind, photo-electrons produced through ionisation of the cometary neutrals by extreme ultraviolet solar radiation, and secondary electrons produced through electron-impact ionisation.</p> <p>The model includes different electron-water collision processes, including elastic, excitation, and ionisation collisions.</p> <p> The electron trajectories are shaped by electric and magnetic fields, which are taken from a 3D collisionless fully-kinetic Particle-in-Cell (PIC) model of the solar wind and cometary plasma  (Deca 2017, 2019). We use a spherically symmetric coma of pure water, which gives a r<sup>-2</sup> profile in the neutral density. Throughout their lifetime, electrons undergo stochastic collisions with neutral molecules, which can degrade the electrons in energy or scatter them.</p> <p>We first validate our model with comparison to results from PIC simulations. We then demonstrate the trapping of electrons in the coma by an ambipolar electric field and the impact of this trapping on the production of cold electrons.</p>

scholarly journals New perspective on qualitative and quantitative indicators of juvenile crime in Russia

2021 ◽  
pp. 44-63
Author(s):  
Akhmat Seit-Umarovich Teunaev ◽  
Mariya Evgen'evna Dubova
Keyword(s):  
Deviant Behavior ◽  
Criminal Activity ◽  
Juvenile Crime ◽  
Qualitative And Quantitative ◽  
Current Trends ◽  
Time Period ◽  
Media Source ◽  
New Perspective ◽  
V Wave ◽  
Quantitative Indicators

The goal of this research consists in determination and analysis of the current trends of juvenile crime in Russia. The subject of this article is the basic patterns of juvenile crime identified by keeping track of its dynamics, modification and activity in Russia from 1991 to 2019, and classified by the authors into separate periods – “waves” in accordance with the “bursts” of such type of crime. It is underlined that the timely identification of factors and conditions that lead to the spate of criminal activity among juveniles in a specific time period allows preventing similar situations in future, as well as contributes to the development of an effective toolset for preventing deviant behavior of teenagers. The empirical basis of this research is comprised of the statistical reports on the state of juvenile crime in Russia that are posted annually on the official websites of the Ministry of Internal Affairs of Russia and the Prosecutor General's Office of the Russian Federation. The authors also lean on the fundamental Russian and foreign research dedicated to the problematic questions of preventing juvenile crime. In the course of studying statistical data that reflect qualitative and quantitative indicators of juvenile crime in Russia from 1991 to 2019, the authors determined five so-called “waves” of juvenile crime: I wave 1991-1997, II wave 1998-2002, III wave 2003-2012, IV wave 2012-2014, and V wave 2014-2019. Examination of media source, publicistic and scientific literature allowed revealing the most probable causes of the sharp increase in criminogenic situation in the juvenile environment. The article also reveals certain negative trends, such as the increase in the rate of grave and especially grave crimes committed by minors.

scholarly journals First ground-based optical analysis of H<sub>β</sub> Doppler profiles close to local noon in the cusp

2006 ◽  
Vol 24 (10) ◽  
pp. 2543-2552 ◽  
Author(s):  
S. C. Robertson ◽  
B. S. Lanchester ◽  
M. Galand ◽  
D. Lummerzheim ◽  
A. B. Stockton-Chalk ◽  
...  
Keyword(s):  
Optical Measurements ◽  
Echelle Spectrograph ◽  
Image Satellite ◽  
High Latitude Region ◽  
The Hours ◽  
Modelling Studies ◽  
Solar Noon ◽  
Latitude Region ◽  
High Throughput Imaging ◽  
Local Noon

Abstract. Observations of hydrogen emissions along the magnetic zenith at Longyearbyen (78.2 N, 15.8 E geographic) are used to investigate the energy and source of protons precipitating into the high latitude region. During the hours around local solar noon (11:00 UT), measurements of the hydrogen Balmer β line are severely affected by sunlight, such that most data until now have been disregarded during these times. Here we use a simple technique to subtract sunlight contamination from such spectral data. An example is shown in which the removal of twilight contamination reveals a brightening of Hβ aurora over Svalbard on 27 November 2000 between 08:00 UT and 10:00 UT, which is centred on magnetic noon (08:48 UT). These data were measured by the High Throughput Imaging Echelle Spectrograph (HiTIES), one instrument on the Southampton-UCL Spectrographic Imaging Facility (SIF). Data from the IMAGE satellite confirms the location of a cusp "spot" over Svalbard at the time of the ground-based measurements, which moved in response to changes in the IMF conditions. A coincident pass of the DMSP F12 satellite provided input spectra for modelling studies of the Hβ profiles, which confirm that the method for removing the twilight contamination is robust. The results described here are the first ground-based optical measurements of Hβ Doppler profiles from the cusp region close to local solar noon, when scattered sunlight swamps the raw data.

scholarly journals Nutrient Timing: A Garage Door of Opportunity?

Nutrients ◽  
2020 ◽  
Vol 12 (7) ◽  
pp. 1948 ◽  
Author(s):  
Shawn M. Arent ◽  
Harry P. Cintineo ◽  
Bridget A. McFadden ◽  
Alexa J. Chandler ◽  
Michelle A. Arent
Keyword(s):  
Improve Performance ◽  
Impact Performance ◽  
Nutrient Timing ◽  
Time Period ◽  
Nutrient Consumption ◽  
Performance Recovery ◽  
New Perspective ◽  
Definition Of ◽  
The Impact ◽  
Anabolic Window

Nutrient timing involves manipulation of nutrient consumption at specific times in and around exercise bouts in an effort to improve performance, recovery, and adaptation. Its historical perspective centered on ingestion during exercise and grew to include pre- and post-training periods. As research continued, translational focus remained primarily on the impact and outcomes related to nutrient consumption during one specific time period to the exclusion of all others. Additionally, there seemed to be increasing emphasis on outcomes related to hypertrophy and strength at the expense of other potentially more impactful performance measures. As consumption of nutrients does not occur at only one time point in the day, the effect and impact of energy and macronutrient availability becomes an important consideration in determining timing of additional nutrients in and around training and competition. This further complicates the confining of the definition of “nutrient timing” to one very specific moment in time at the exclusion of all other time points. As such, this review suggests a new perspective built on evidence of the interconnectedness of nutrient impact and provides a pragmatic approach to help frame nutrient timing more inclusively. Using this approach, it is argued that the concept of nutrient timing is constrained by reliance on interpretation of an “anabolic window” and may be better viewed as a “garage door of opportunity” to positively impact performance, recovery, and athlete availability.

Investigating the Jet Comminuting Process in Cuttings Transport by Coupling the CFD/DEM Method and Bonded-Particle Model

SPE Journal ◽  
2019 ◽  
Vol 24 (05) ◽  
pp. 2020-2032 ◽  
Author(s):  
Yongsheng Liu ◽  
Deli Gao ◽  
Xin Li ◽  
Xing Qin ◽  
He Li ◽  
...  
Keyword(s):  
Effective Means ◽  
Element Model ◽  
Secondary Development ◽  
Particle Model ◽  
Compression Tests ◽  
Cuttings Transport ◽  
Horizontal Drilling ◽  
Bonded Particle Model ◽  
Drilling Operations ◽  
New Perspective

Summary Jet comminuting technology has proved to be an effective means of solid particle pulverization, and current research attempts to introduce it for drilling work to reduce cuttings size, because smaller cuttings are easy to circulate out of the bottom, thus can effectively prevent the formation of cuttings bed, especially in horizontal drilling. In this paper, the feasibility of cuttings’ comminution by jet is studied by means of numerical simulation with secondary development. The coupling analysis methods—including the computational–fluid–dynamics/discrete–element–model (CFD/DEM) modeling for the interaction between fluid and cuttings and the particle replacement and bonding modeling for cuttings breakage—are used to characterize the jet comminuting process of cuttings. Input parameters of simulation are reliable and verified by uniaxial compression tests. Case studies presented here indicate that cuttings can be considerably accelerated by 20 to 30 m/s through the throat, which provides a good effective speed for the cuttings. After being accelerated by the fluid and crushed with the target, the vast majority of cuttings results in smaller debris. Also, increasing the inlet speed affects the crushing efficiency. The inclination of the target at near 65° shows good results. This paper proposes a new perspective to introduce the jet comminuting technique for drilling operations, and its findings could help in guiding engineering design in the future.

To “Labour with a Greater Sense of Safety”: First Aid, Civic Duty, and Risk Management in the British Working Class, 1870–1914

2019 ◽  
Vol 54 (2) ◽  
pp. 526-545
Author(s):  
Esther Isaac ◽  
Alisa Bajramovic ◽  
Isabel Miller ◽  
Chelsea Pan ◽  
Emily Ratté ◽  
...  
Keyword(s):  
Working Class ◽  
First Aid ◽  
Daily Lives ◽  
Class Culture ◽  
Civic Duty ◽  
Time Period ◽  
First Aid Training ◽  
The Face ◽  
New Perspective ◽  
Safety First

Abstract Much has been written about British ideals of citizenship in the face of heightened social discord, particularly in times of war. There is a lack of analysis, however, relating notions of civic duty to the risks faced by British people in their everyday lives. Further, most scholarship on civic duty as it relates to the perception and management of risk focuses on the twentieth century and, in particular, the World Wars. This article seeks to examine civic participation in an earlier time period—from 1870 to 1914—through the lens of the civilian first-aid movement. We argue that first aid presented working-class men with a way to manage novel forms of risk introduced by new and dangerous technologies in the workplace and in their daily lives. Applying first-aid training provided these men with a way to participate in a burgeoning working-class culture of self-reliance, altruism, and civic duty. This article contributes to the discussion surrounding expressions of citizenship in the civilian realm and presents a new perspective on the significance of the British first-aid movement.

scholarly journals Using CME Progenitors to Assess CME Geoeffectiveness

2021 ◽  
Vol 257 (2) ◽  
pp. 33
Author(s):  
Kashvi Mundra ◽  
V. Aparna ◽  
Petrus Martens
Keyword(s):  
Magnetic Field ◽  
Extreme Ultraviolet ◽  
Geomagnetic Storms ◽  
Solar Surface ◽  
Axial Direction ◽  
Solar Observatory ◽  
Field Orientation ◽  
Heliospheric Observatory ◽  
Doppler Imager ◽  
Time Period

Abstract There have been a few previous studies claiming that the effects of geomagnetic storms strongly depend on the orientation of the magnetic cloud portion of coronal mass ejections (CMEs). Aparna & Martens, using halo-CME data from 2007 to 2017, showed that the magnetic field orientation of filaments at the location where CMEs originate on the Sun can be used to credibly predict the geoeffectiveness of the CMEs being studied. The purpose of this study is to extend their survey by analyzing the halo-CME data for 1996–2006. The correlation of filament axial direction on the solar surface and the corresponding Bz signatures at L1 are used to form a more extensive analysis for the results previously presented by Aparna & Martens. This study utilizes Solar and Heliospheric Observatory Extreme-ultraviolet Imaging Telescope 195 Å, Michelson Doppler Imager magnetogram images, and Kanzelhöhe Solar Observatory and Big Bear Solar Observatory Hα images for each particular time period, along with ACE data for interplanetary magnetic field signatures. Utilizing all these, we have found that the trend in Aparna & Martens’ study of a high likelihood of correlation between the axial field direction on the solar surface and Bz orientation persists for the data between 1996 and 2006, for which we find a match percentage of 65%.

Two-dimensional high-latitude thermospheric modeling: A comparison between moderate and extremely disturbed conditions

1991 ◽  
Vol 69 (8-9) ◽  
pp. 1007-1031 ◽  
Author(s):  
C. A. Chang ◽  
J.-P. St.-Maurice
Keyword(s):  
Joule Heating ◽  
Stokes Equations ◽  
Extreme Ultraviolet ◽  
Complex Structure ◽  
Zonal Flow ◽  
Global Scale ◽  
Momentum Equation ◽  
Temperature Fields ◽  
Two Dimensional ◽  
Drift Motion

A set of two-dimensional nonlinear calculations has been done to simulate the auroral region electrojet and to examine the effect of the electric field on the dynamics and thermodynamics of the thermosphere. A large number of physical and dynamical processes in the ionosphere have been considered, including the ion-drag force, the Coriolis force, gravitation, Joule heating, viscous heating and viscous work, solar extreme ultraviolet heating, thermal conduction, and cooling to space owing to infrared radiation of different species. Navier–Stokes equations for a compressible, viscous and thermal conducting fluid flow with source terms have been solved by a MacCormack explicit, alternative forward-backward finite differencing scheme in spherical coordinates. Results have been recorded at various time intervals for three hours simulation time, for altitudes between 80 and 450 km, and from the north pole to the equator. In addition to a strong zonal drift motion and to the basic upward and meridional motion away from the heated region, we obtain a complex structure of waves involving meridional and vertical winds, as well as the density and temperature fields. This computation suggests that waves play a much more important role than ordinary diffusion of energy and momentum is spreading the effects of the disturbances away from the electrojet region. The net result is that there is, strictly speaking, no steady state reached by the neutrals except for the bulk of the zonal flow. A second major feature that we obtain is that nonlinear terms can often dominate the momentum equation, which can reduce the magnitude of the zonal flow by a considerable amount, and can displace the region of maximum neutral flow away from where the electrojet is. The nonlinear terms are also responsible for the formation of a neutral density 'hole' at nonelectrojet latitudes. This hole is found below the region where Joule heating reaches its peak value and is used to enhance the neutral densities at high altitudes on a global scale.

Strong Competition Equals Strong Reforms? A New Perspective on Corporate Tax Reforms in 15 EU Countries (1998–2011)

2016 ◽  
Vol 12 (2) ◽  
pp. 301-346
Author(s):  
Alexander von Kulessa ◽  
Georg Wenzelburger
Keyword(s):  
Tax Competition ◽  
Qualitative Comparative Analysis ◽  
Partisan Politics ◽  
Corporate Tax ◽  
Tax Reforms ◽  
Eu Countries ◽  
Eu Member States ◽  
Time Period ◽  
Regression Techniques ◽  
New Perspective

AbstractAlthough many EU countries have reduced corporate taxes in the recent years, there is still a substantial variance between the 12 oldest EU-member states. This contribution revisits this variation and analyses the determinants of corporate tax reforms and their magnitude from a perspective which is new in two respects. First, we combine logistic panel regression and fuzzy-set qualitative comparative analysis (fsQCA) analysis allowing for an integration of qualitative assessments of tax reforms in the QCA analysis. This adds to the existing studies on tax reform which almost exclusively rely on regression techniques. Second, we focus on the time period 1998–2011 where we expect tax competition to be especially intense. The results of our analyses confirm the major impact of tax competition on national corporate tax policies. This relationship dominates the regression analyses as well as the fsQCA. Furthermore, our findings allow nuancing the existing results on the influence of institutional constraints and partisan politics.

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