scholarly journals Spatio-temporal evolution of electric field inside a microwave discharge plasma during initial phase of ignition and its effect on power coupling

2019 ◽  
Vol 26 (4) ◽  
pp. 043507 ◽  
Author(s):  
C. Mallick ◽  
M. Bandyopadhyay ◽  
R. Kumar
Keyword(s):  
Electric Field ◽  
Initial Phase ◽  
Discharge Plasma ◽  
Microwave Discharge ◽  
Temporal Evolution ◽  
Power Coupling ◽  
Spatio Temporal

Effect of Mass and Charge of Ionic Species on Spatio-Temporal Evolution of Transient Electric Field in CCP Discharges

2015 ◽  
Vol 55 (4) ◽  
pp. 331-336 ◽  
Author(s):  
S. Sharma ◽  
S. K. Mishra ◽  
P. K. Kaw ◽  
M. M. Turner ◽  
S. K. Karkari
Keyword(s):  
Electric Field ◽  
Temporal Evolution ◽  
Ionic Species ◽  
Spatio Temporal ◽  
Transient Electric Field

scholarly journals Evolution of Microwave Electric Field on Power Coupling to Plasma during Ignition Phase

2020 ◽  
Author(s):  
Chinmoy Mallick ◽  
Mainak Bandyopadhyay ◽  
Rajesh Kumar
Keyword(s):  
Electric Field ◽  
Electric Fields ◽  
Critical Density ◽  
Coupling Mechanism ◽  
Ignition Process ◽  
Ion Acoustic Wave ◽  
Power Coupling ◽  
Gas Ignition ◽  
Spatio Temporal ◽  
Coupling Processes

During the gas ignition process, the plasma and the microwave electric fields are evolved with time together in the plasma volume. The spatio-temporal evolution pattern of microwave-radiated plasma parameters is reported here, highlighting the role of these electric fields on power coupling processes. Evolutions of electric field and so power coupling processes are calculated using the finite element method (FEM). It is observed that the main power coupling mechanism is electron cyclotron resonance (ECR) method; however, with the evolution of plasma, the mode shifts from ECR to off-ECR-type heating with time. Off-ECR heating in the form of upper hybrid resonance (UHR) method, electrostatic (ES) ion acoustic wave heating method is important heating mechanisms during highly dense plasma condition, when density is above critical density for launched frequency, 2.45 GHz. The conclusions on the shifting of heating mechanisms are also drawn based on the 3D maps of spatio-temporal plasma density and hot electron temperature evolution.

Spatio-temporal evolution and dynamic origin of Jurassic-Cretaceous magmatism in the South China Block

2021 ◽  
Vol 217 ◽  
pp. 103605
Author(s):  
Xianzhi Cao ◽  
Nicolas Flament ◽  
Sanzhong Li ◽  
R. Dietmar Müller
Keyword(s):  
South China ◽  
Temporal Evolution ◽  
South China Block ◽  
The South ◽  
Spatio Temporal ◽  
Cretaceous Magmatism

scholarly journals Spatio-temporal evolution and influencing mechanism of the COVID-19 epidemic in Shandong province, China

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Jinlong Shi ◽  
Xing Gao ◽  
Shuyan Xue ◽  
Fengqing Li ◽  
Qifan Nie ◽  
...  
Keyword(s):  
Prevention And Control ◽  
Temporal Evolution ◽  
Geographical Location ◽  
Shandong Province ◽  
Control Measures ◽  
Middle Aged ◽  
Health Crisis ◽  
Aged People ◽  
Spatio Temporal ◽  
And Control

AbstractThe novel coronavirus pneumonia (COVID-19) outbreak that emerged in late 2019 has posed a severe threat to human health and social and economic development, and thus has become a major public health crisis affecting the world. The spread of COVID-19 in population and regions is a typical geographical process, which is worth discussing from the geographical perspective. This paper focuses on Shandong province, which has a high incidence, though the first Chinese confirmed case was reported from Hubei province. Based on the data of reported confirmed cases and the detailed information of cases collected manually, we used text analysis, mathematical statistics and spatial analysis to reveal the demographic characteristics of confirmed cases and the spatio-temporal evolution process of the epidemic, and to explore the comprehensive mechanism of epidemic evolution and prevention and control. The results show that: (1) the incidence rate of COVID-19 in Shandong is 0.76/100,000. The majority of confirmed cases are old and middle-aged people who are infected by the intra-province diffusion, followed by young and middle-aged people who are infected outside the province. (2) Up to February 5, the number of daily confirmed cases shows a trend of “rapid increase before slowing down”, among which, the changes of age and gender are closely related to population migration, epidemic characteristics and intervention measures. (3) Affected by the regional economy and population, the spatial distribution of the confirmed cases is obviously unbalanced, with the cluster pattern of “high–low” and “low–high”. (4) The evolution of the migration pattern, affected by the geographical location of Wuhan and Chinese traditional culture, is dominated by “cross-provincial” and “intra-provincial” direct flow, and generally shows the trend of “southwest → northeast”. Finally, combined with the targeted countermeasures of “source-flow-sink”, the comprehensive mechanism of COVID-19 epidemic evolution and prevention and control in Shandong is revealed. External and internal prevention and control measures are also figured out.

scholarly journals Adjoint-based direct data assimilation of GNSS time series for optimizing frictional parameters and predicting postseismic deformation following the 2003 Tokachi-oki earthquake

2020 ◽  
Vol 72 (1) ◽  
Author(s):  
Masayuki Kano ◽  
Shin’ichi Miyazaki ◽  
Yoichi Ishikawa ◽  
Kazuro Hirahara
Keyword(s):  
Time Series ◽  
Data Assimilation ◽  
Evaluation Method ◽  
Temporal Evolution ◽  
Recovery Process ◽  
Postseismic Deformation ◽  
Coseismic Slip ◽  
Megathrust Earthquakes ◽  
Spatio Temporal ◽  
Gnss Time Series

Abstract Postseismic Global Navigation Satellite System (GNSS) time series followed by megathrust earthquakes can be interpreted as a result of afterslip on the plate interface, especially in its early phase. Afterslip is a stress release process accumulated by adjacent coseismic slip and can be considered a recovery process for future events during earthquake cycles. Spatio-temporal evolution of afterslip often triggers subsequent earthquakes through stress perturbation. Therefore, it is important to quantitatively capture the spatio-temporal evolution of afterslip and related postseismic crustal deformation and to predict their future evolution with a physics-based simulation. We developed an adjoint data assimilation method, which directly assimilates GNSS time series into a physics-based model to optimize the frictional parameters that control the slip behavior on the fault. The developed method was validated with synthetic data. Through the optimization of frictional parameters, the spatial distributions of afterslip could roughly (but not in detail) be reproduced if the observation noise was included. The optimization of frictional parameters reproduced not only the postseismic displacements used for the assimilation, but also improved the prediction skill of the following time series. Then, we applied the developed method to the observed GNSS time series for the first 15 days following the 2003 Tokachi-oki earthquake. The frictional parameters in the afterslip regions were optimized to A–B ~ O(10 kPa), A ~ O(100 kPa), and L ~ O(10 mm). A large afterslip is inferred on the shallower side of the coseismic slip area. The optimized frictional parameters quantitatively predicted the postseismic GNSS time series for the following 15 days. These characteristics can also be detected if the simulation variables can be simultaneously optimized. The developed data assimilation method, which can be directly applied to GNSS time series following megathrust earthquakes, is an effective quantitative evaluation method for assessing risks of subsequent earthquakes and for monitoring the recovery process of megathrust earthquakes.

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