Spatio-temporal evolution of two-plasmon decay in homogeneous plasma

AbstractA hydrodynamic model of two-plasmon decay in a homogeneous plasma slab near the quarter-critical density is utilized to study the spatio-temporal evolution of the daughter electron plasma waves in plasma in the course of the instability. The influence of laser and plasma parameters on the evolution of the amplitudes of the participating waves is discussed, assuming that the secondary coupling of two daughter electron plasma waves with an ion-acoustic wave is the principal mechanism of saturation of the instability. The impact of inherently non-resonant nature of this secondary coupling on the development of TPD is investigated for the first time and it is shown to significantly influence the electron plasma wave dynamics. Its inclusion leads to non-uniformity of the spatial profile of the instability and causes the burst-like pattern of the instability development, which should result in the burst-like hot-electron production in homogeneous plasma.

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Collective absorption of laser radiation in plasma at sub-relativistic intensities

High Power Laser Science and Engineering ◽

10.1017/hpl.2019.25 ◽

2019 ◽

Vol 7 ◽

Cited By ~ 3

Author(s):

Y. J. Gu ◽

O. Klimo ◽

Ph. Nicolaï ◽

S. Shekhanov ◽

S. Weber ◽

...

Keyword(s):

Inertial Confinement Fusion ◽

Stimulated Raman Scattering ◽

Laser Energy ◽

Brillouin Scattering ◽

Critical Density ◽

Plasma Waves ◽

High Amplitude ◽

Inertial Confinement ◽

Hot Electron ◽

Plasma Parameters

Processes of laser energy absorption and electron heating in an expanding plasma in the range of irradiances $I\unicode[STIX]{x1D706}^{2}=10^{15}{-}10^{16}~\text{W}\,\cdot \,\unicode[STIX]{x03BC}\text{m}^{2}/\text{cm}^{2}$ are studied with the aid of kinetic simulations. The results show a strong reflection due to stimulated Brillouin scattering and a significant collisionless absorption related to stimulated Raman scattering near and below the quarter critical density. Also presented are parametric decay instability and resonant excitation of plasma waves near the critical density. All these processes result in the excitation of high-amplitude electron plasma waves and electron acceleration. The spectrum of scattered radiation is significantly modified by secondary parametric processes, which provide information on the spatial localization of nonlinear absorption and hot electron characteristics. The considered domain of laser and plasma parameters is relevant for the shock ignition scheme of inertial confinement fusion.

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IMPACT OF THE PORT STRUCTURE IN THE SPATIO-TEMPORAL EVOLUTION OF THE SEDIMENTARY AND BATHYMETRIC CHARACTERISTICS OF A MOROCCAN ATLANTIC BAY, STUDY CASE BAY OF SAFI CITY

ISPRS - International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences ◽

10.5194/isprs-archives-xlvi-4-w3-2021-215-2022 ◽

2022 ◽

Vol XLVI-4/W3-2021 ◽

pp. 215-221

Author(s):

A. Minoubi ◽

M. Bouchkara ◽

K. El Khalidi ◽

M. Chaibi ◽

M. Ayt Ougougdal ◽

...

Keyword(s):

Environmental Changes ◽

Temporal Evolution ◽

Atlantic Coast ◽

Sedimentary Facies ◽

Hydrodynamic Conditions ◽

Study Case ◽

Spatio Temporal ◽

The Impact ◽

Port Construction

Abstract. This study focuses on morpho-sedimentary changes in the bay of Safi (Atlantic coast of Morocco), due to a progressive extension of the port. For this purpose, several bathymetric and sedimentary surveys carried out by the Hydrographic and Oceanographic Service of the Navy (SHOM) in 1892, 1906 and 1940 respectively, coupled with a bathymetric and sedimentary measurement mission in 2009, were analyzed to understand the impact of the port developments on the bottom of Safi Bay. This analysis consists of making maps of the evolution of (i) sedimentary facies (of different dates 1892, 1906, 1940 and 2009) and (ii) the shallow seabed of the three periods 1892–1906, 1906–1940 and 1940–2009. The sedimentary facies maps show that the facies appear unstable and evolve intermittently in response to environmental changes in the bay (port construction and expansion). In addition, the overlay of the bathymetric maps indicates that the bay has undergone changes (lowering, stability, and raising) controlled by hydrodynamic conditions before, during, and even after harbor construction. Analysis of the data showed that the expansion of the port often reshaped the morphology of the bay's seabed. The consequences of these evolutions are the appearance of the fattening or the erosion of the bank and the filling of small depressions of sediments. This evolution is reflected in the modification of the funds near the port and the beach of Safi.

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Spatio-Temporal Evolution and Mechanism Analysis of China’s Regional Innovation Efficiency

Sustainability ◽

10.3390/su131911089 ◽

2021 ◽

Vol 13 (19) ◽

pp. 11089

Author(s):

Zhen Xu ◽

Xiang Zhu ◽

Guoen Wei ◽

Xiao Ouyang

Keyword(s):

Temporal Evolution ◽

Spillover Effects ◽

Essential Elements ◽

Eastern Region ◽

Mechanism Analysis ◽

Regional Innovation ◽

Evolution Pattern ◽

Evolution Characteristics ◽

Spatio Temporal ◽

The Impact

Improving regional innovation efficiency is the key to developing an innovative country. Exploring the spatio-temporal evolution characteristics of regional innovation efficiency is crucial in the formulation of regional policies and the choice of innovation models. This study used the superdata envelopment analysis method with undesirable outputs in evaluating the innovation efficiency of Chinese provinces. To assess the spatial spillover effects of innovation factors, the spatial autocorrelation and spatial Durbin model were adopted to characterize the spatio-temporal evolution, spatial correlation, and mechanisms of innovation efficiency. The highlights of the results are as follows: (1) The time-series changes in innovation efficiency showed a general trend from declining to increasing. (2) There were pronounced regional differences in innovation efficiency. The innovation efficiencies at the provincial level evolved from being decentralized to concentrated. The innovation efficiency was relatively stable in the eastern region and increased significantly in the central and western regions. The east–center–west evolution pattern gradually weakened. (3) The innovative efficiency exhibited spatial dependence, and the spatial agglomeration continued to increase. The extent of hot spots expanded, while cold spots shrunk slightly. (4) The scientific research environment, entrepreneurial environment, labor quality, and market environment were the essential elements that improved innovation efficiency. The impact of the different factors on innovation efficiency at different periods exhibited significant spatial heterogeneity.

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Spatio-temporal relational evaluation of the Beijing water crisis and planning implementation from 1949 to 2013

Water Policy ◽

10.2166/wp.2018.107 ◽

2018 ◽

Vol 20 (3) ◽

pp. 490-509 ◽

Cited By ~ 1

Author(s):

Wei Fu ◽

Kongjian Yu ◽

Dihua Li

Keyword(s):

Temporal Evolution ◽

Water Security ◽

Temporal Analysis ◽

Water Shortage ◽

Relational Model ◽

Water Crisis ◽

Water Planning ◽

Planning Implementation ◽

Spatio Temporal ◽

The Impact

Abstract Due to a lack of evaluation of the implementation of water planning policies, based on long-term spatio-temporal analysis, this research uses Beijing as an empirical case study to bridge this gap. We analyze the spatio-temporal evolution of water problems and water planning implementations. Content analysis, cluster analysis, and spatial interpolation analysis are used to illustrate the spatio-temporal evolution of water planning implementation. In addition, a grey relational model is developed to determine the impact of the most relevant implementation objects on each water issue. The results indicate that the Beijing water crisis evolves from the center outwards in a planar expansion. However, the water plan implementation shows linear and point characteristics. The majority of implementation categories consist of single-function infrastructure. The implemented categories ‘which show a significant implementation peak’ influence more than one water issue. The categories ‘that were implemented at a steady rate’ have a high relational grade with both surface and underground water shortage problems. Different implementation types from different planning categories may have simultaneous effects on one kind of water problem. Thus, improving water governance is the key to water security in Beijing. This study may serve as a reference for future water planning in other cities.

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A Study of Centre-fed Antiphase Circular Antennas in a Warm Plasma

Australian Journal of Physics ◽

10.1071/ph800539 ◽

1980 ◽

Vol 33 (3) ◽

pp. 539

Author(s):

KR Soni ◽

CL Arora

Keyword(s):

Plasma Waves ◽

Electron Plasma ◽

Hydrodynamic Theory ◽

Plasma Medium ◽

Plasma Parameters ◽

Radiation Characteristics ◽

Circular Arc ◽

Radiation Properties ◽

Tem Mode ◽

Warm Plasma

The radiation characteristics of a centre-fed antiphase circular arc antenna immersed in a warm electron plasma are studied using linearized hydrodynamic theory. The effects of antenna and plasma parameters on the radiation properties have been studied by computing the results and presenting them graphically. It is found that, whereas the power radiated in the TEM mode depends on the length as well as on the angle of the arc antenna, the power in the LP mode is independent of the angle and depends only on the length of the arc. It is also found that the power in the LP mode is relatively much larger in the case of small angled centre-fed antiphase arc antennas. Hence small angled arcs should be suitable for the launching of plasma waves, whereas large angled arcs will be more useful for communication through a plasma medium.

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Cambio de área glaciar en el volcán Maipo (Andes Centrales), una aproximación morfométrica: 4 décadas de registros satelitales

Andean geology ◽

10.5027/andgeov49n1-3369 ◽

2021 ◽

Vol 49 (1) ◽

Author(s):

Andrés Lo Vecchio Repetto ◽

Mario Candela ◽

Daniel Falaschi ◽

Federico Otero ◽

María Alejandrina Videla ◽

...

Keyword(s):

Loss Rate ◽

Temporal Evolution ◽

Climatic Conditions ◽

P Value ◽

Relative Area ◽

Glacier Area ◽

Landsat Images ◽

Rugged Topography ◽

Spatio Temporal ◽

The Impact

Current climatic conditions in Central Andes (CA) (31-36 °S) have triggered the reduction of glacier area. Although CA are geographically circumscribed to an area under the same macroclimatic domain, their rugged topography creates several topoclimates as response to the effects of elevation, slope and aspect (morphometric factors). This study explores the impact of morphometric factors on the evolution of the glacial surface located above of Maipo volcano (34°09'50''S; 69°49'53''W). Through the use of 11 LANDSAT images (MSS, TM and OLI), the spatio-temporal evolution (period 1976-2020) of the glacier area was reconstructed. On this period, glacier area was reduced by 6 ± 0.5 km2 (-0.14 ± 0.01 km2a-1), equal to 63 % of 1976 glacial area (9.6 ± 0.5 km2). Fifty percent of the reduction occurred between 3,900 and 4,000 m elevation, with absolute losses towards lower elevations. In addition, it was detected that for every 100 m of ascent the relative area loss rate decreased 0.1 %a-1 (R2 = 0.81; p-value

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The Impact of modern Tobacco Agriculture planning on the Spatio-temporal Evolution of Urban construction Land

Tobacco Regulatory Science ◽

10.18001/trs.7.5.12 ◽

2021 ◽

Vol 7 (5) ◽

pp. 938-949

Author(s):

Miao Yahui ◽

Jiang Ce ◽

Gu Zifan ◽

Xi Zenglei

Keyword(s):

Time Series ◽

Temporal Evolution ◽

Market Demand ◽

Continuous Growth ◽

Construction Land ◽

Long Time Series ◽

Urban Construction ◽

Long Time ◽

Spatio Temporal ◽

The Impact

In recent years, the world tobacco industry has shown a trend of continuous growth in market demand and increasingly concentrated tobacco market, which brings new opportunities to the tobacco agriculture development. However, the modern tobacco agriculture is bound to occupy a large amount of agricultural land, which will have a certain impact on the distribution of urban construction land (UCL). Therefore, reasonable and effective modern tobacco agricultural planning plays a vital role in promoting modern agricultural and urban development.In this paper, we took Baiyangdian basin as the study area, applying the long time series nighttime light (NTL) data to extract UCL and analysing the impact of modern tobacco agriculture planning on the spatio-temporal evolution of UCL. Firstly, we used a power function model to fit the two kinds of international mainstream NTL data to form a long time series NTL dataset from 1992 to 2018 to make the NTL data comparable over a long time. Then, the threshold segmentation method based on land use data calibration was applied to extract the UCL in Baiyangdian basin in 2000, 2010 and 2018, and to analyze its spatio-temporal evolution characteristics and patterns by combining the landscape metrics and gravity model. The results show that the UCL in Baiyangdian basin shows the expansion trend centered on the main urban area of Baoding City, land intensification degree has increased, and the modern tobacco agriculture planning has a profound impact on the spatio-temporal distribution of UCL. Our study will provide technical support and experience for the scientific modern tobacco agriculture planning.

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