scholarly journals Parametric Study of Resistive Plasmoid Instability

2021 ◽  
Vol 8 ◽  
Author(s):  
Hossein Lotfi ◽  
Mahboub Hosseinpour
Keyword(s):  
Growth Rate ◽  
Parametric Study ◽  
Amplitude Ratio ◽  
Scaling Relations ◽  
Nonlinear Growth ◽  
Plane Field ◽  
Guide Field ◽  
Mhd Simulations ◽  
Instability Growth ◽  
Linear And Nonlinear

By using 2.5-dimensional resistive MHD simulations, dynamics of the plasmoid instability in a Harris current sheet has been studied with taking into account two main controlling parameters: the plasma-β in the range (0 < β < 1) and the amplitude ratio of magnetic guide field to the reconnection plane field in three different cases with zero, uniform, and non-uniform guide field. Varying the plasma-β changes the plasma compressibility which affects significantly on the linear and nonlinear growth rates of the plasmoid instability. For each of three cases, some associated scaling relations between the instability growth rate, the plasma-β and the magnitude of guide field are obtained.

Global Dynamics of a Holling-II Amensalism System with Nonlinear Growth Rate and Allee Effect on the First Species

2021 ◽  
Vol 31 (03) ◽  
pp. 2150050
Author(s):  
Demou Luo ◽  
Qiru Wang
Keyword(s):  
Growth Rate ◽  
Allee Effect ◽  
Global Dynamics ◽  
Asymptotically Stable ◽  
Globally Asymptotically Stable ◽  
Nonlinear Growth ◽  
Trivial Equilibrium ◽  
Existence And Stability ◽  
Stable Equilibria ◽  
Theoretical Results

Of concern is the global dynamics of a two-species Holling-II amensalism system with nonlinear growth rate. The existence and stability of trivial equilibrium, semi-trivial equilibria, interior equilibria and infinite singularity are studied. Under different parameters, there exist two stable equilibria which means that this model is not always globally asymptotically stable. Together with the existence of all possible equilibria and their stability, saddle connection and close orbits, we derive some conditions for transcritical bifurcation and saddle-node bifurcation. Furthermore, the global dynamics of the model is performed. Next, we incorporate Allee effect on the first species and offer a new analysis of equilibria and bifurcation discussion of the model. Finally, several numerical examples are performed to verify our theoretical results.

Suppression of Baroclinic Instabilities in Buoyancy-Driven Flow over Sloping Bathymetry

2017 ◽  
Vol 47 (1) ◽  
pp. 49-68 ◽  
Author(s):  
Robert D. Hetland
Keyword(s):  
Growth Rate ◽  
Linear Instability ◽  
Linear Stability Theory ◽  
Buoyancy Frequency ◽  
Bottom Slope ◽  
Coriolis Parameter ◽  
Plume Front ◽  
Instability Theory ◽  
Instability Growth ◽  
Flow Configurations

AbstractBaroclinic instabilities are ubiquitous in many types of geostrophic flow; however, they are seldom observed in river plumes despite strong lateral density gradients within the plume front. Supported by results from a realistic numerical simulation of the Mississippi–Atchafalaya River plume, idealized numerical simulations of buoyancy-driven flow are used to investigate baroclinic instabilities in buoyancy-driven flow over a sloping bottom. The parameter space is defined by the slope Burger number S = Nf−1α, where N is the buoyancy frequency, f is the Coriolis parameter, and α is the bottom slope, and the Richardson number Ri = N2f2M−4, where M2 = |∇Hb| is the magnitude of the lateral buoyancy gradients. Instabilities only form in a subset of the simulations, with the criterion that SH ≡ SRi−1/2 = Uf−1W−1 = M2f−2α 0.2, where U is a horizontal velocity scale and SH is a new parameter named the horizontal slope Burger number. Suppression of instability formation for certain flow conditions contrasts linear stability theory, which predicts that all flow configurations will be subject to instabilities. The instability growth rate estimated in the nonlinear 3D model is proportional to ωImaxS−1/2, where ωImax is the dimensional growth rate predicted by linear instability theory, indicating that bottom slope inhibits instability growth beyond that predicted by linear theory. The constraint SH 0.2 implies a relationship between the inertial radius Li = Uf−1 and the plume width W. Instabilities may not form when 5Li > W; that is, the plume is too narrow for the eddies to fit.

scholarly journals The Study of Thermal Conditions on Weibel Instability

2015 ◽  
Vol 2015 ◽  
pp. 1-6
Author(s):  
M. Mahdavi ◽  
H. Khanzadeh
Keyword(s):  
Growth Rate ◽  
Thermal Conditions ◽  
Ion Scattering ◽  
Weibel Instability ◽  
Anisotropic Temperature ◽  
Instability Growth ◽  
Limiting Condition ◽  
Limiting Case ◽  
Background Ions ◽  
Electromagnetic Instability

Weibel electromagnetic instability has been studied analytically in relativistic plasma with high parallel temperature, where|α=(mc2/T∥)(1+p^⊥2/m2c2)1/2|≪1and while the collision effects of electron-ion scattering have also been considered. According to these conditions, an analytical expression is derived for the growth rate of the Weibel instability for a limiting case of|ζ=α/2(ω′/ck)|≪1, whereω′is the sum of the wave frequency of instability and the collision frequency of electrons with background ions. The results show that in the limiting conditionα≪1there is an unusual situation of the Weibel instability so thatT∥≫T⊥, while in the classic Weibel instabilityT∥≪T⊥. The obtained results show that the growth rate of the Weibel instability will be decreased due to an increase in the number of collisions and a decrease in the anisotropic temperature by the increasing of plasma density, while the increase of the parameterγ^⊥=(1+p^⊥2/m2c2)1/2leads to the increase of the Weibel instability growth rate.

scholarly journals Orbit width scaling of TAE instability growth rate

1995 ◽  
Author(s):  
H.V. Wong ◽  
H.L. Berk ◽  
B.N. Breizman
Keyword(s):  
Growth Rate ◽  
Instability Growth Rate ◽  
Instability Growth

scholarly journals Energy Price and Energy Efficiency in China: A Linear and Nonlinear Empirical Investigation

Energies ◽  
2020 ◽  
Vol 13 (16) ◽  
pp. 4068 ◽  
Author(s):  
Peng Hou ◽  
Yilin Li ◽  
Yong Tan ◽  
Yuanjie Hou
Keyword(s):  
Economic Growth ◽  
Growth Rate ◽  
Energy Efficiency ◽  
Economic Development ◽  
Energy Price ◽  
Effect Analysis ◽  
Economic Growth Rate ◽  
Development Level ◽  
Linear And Nonlinear ◽  
The Impact

The empirical conclusions regarding the relationship between energy price and energy efficiency are relatively mixed. This paper systematically examines the influence of energy price on energy efficiency in China based on data from 30 provinces between 2003 and 2017, using linear and nonlinear effect analysis. We found that the impact of energy price on energy efficiency in China was positive in general. However, there existed heterogeneous effects of energy price on energy efficiency in various regions, and the effect differed with differences in energy efficiency levels based on the panel quantile regression analysis. Finally, the nonlinear effect analysis based on the panel threshold model indicated that the effect of energy price on energy efficiency increased with the rise of the environmental regulation level and economic growth rate, while it decreased with the ascent of the degree of energy price distortion and economic development level. In particular, when the value of a region’s economic development level and economic growth rate was within a certain range, the impact was not statistically significant. Overall, these findings contribute to a deeper understanding regarding the effect of energy price on energy efficiency in China.

Numerical investigations on the effects of geometrical parameters on free electron laser instability

2008 ◽  
Vol 74 (6) ◽  
pp. 741-747
Author(s):  
B. S. SHARMA ◽  
N. K. JAIMAN
Keyword(s):  
Growth Rate ◽  
Electron Beam ◽  
Free Electron ◽  
Free Electron Laser ◽  
Instability Growth Rate ◽  
Magnetized Plasma ◽  
Geometrical Parameters ◽  
Uniform Density ◽  
Backward Wave Oscillator ◽  
Instability Growth

AbstractIn this paper we numerically investigate the effects of various geometrical parameters of a backward wave oscillator (BWO), filled with a magnetized plasma of uniform density and driven by a mild relativistic solid electron beam, on the instability growth rate (Γ) of a free electron laser (FEL). The FEL instability is numerically calculated and the result is compared with the instability growth rate of an annular electron beam for the same set of parameters. The instability growth for a solid electron beam scales inversely to the seventh power of relativistic gamma factor γ0 and directly proportional to the corrugation amplitude.

Kinetic study of instability growth rate in a helicon plasma discharge source

2017 ◽  
Vol 57 (6-7) ◽  
pp. 272-281
Author(s):  
Rokhsare Jaafarian ◽  
Alireza Ganjovi ◽  
Gholam Reza Etaati
Keyword(s):  
Growth Rate ◽  
Kinetic Study ◽  
Plasma Discharge ◽  
Instability Growth Rate ◽  
Helicon Plasma ◽  
Discharge Source ◽  
Instability Growth
Sign in / Sign up

Export Citation Format

Share Document