1,135 research outputs found
Overview Of Nonlinear Kinetic Instabilities
Get PDFThe saturation of shear Alfven-like waves by alpha particles is presented from the general viewpoint of determining the saturation mechanisms of basic waves in a plasma destabilized by a perturbing source of free energy. The formalism is reviewed and then followed by analyses of isolated mode saturation far from and close to marginal stability. The effect of multiple waves that are isolated or are overlapping is then discussed. The presentation is concluded with a discussion of a non-conventional quasilinear theory that covers both extreme cases as well as the intermediate regime between the extremes.Physic
Letter: R.F. Pettigrew to H.L. Loucks, May 30, 1916
No full textR.F. Pettigrew articulates to H.L. Loucks his distaste for the book that Loucks recommended to him. Pettigrew also mentions that he would prefer to remain distanced from any conference with the author of the book. Pettigrew expresses great admiration and interest in Loucks' manuscript and desire to read it further
Effect of phase space folding on the accuracy of the Berk–Breizman cubic equation
No full textInternational audienceWe assess the quantitative accuracy of the Berk–Breizman (BB) cubic wave equation that has been previously derived to describe the initial nonlinear behavior of kinetic instabilities (Berk et al 1996 Phys. Rev. Lett. 76 1256–9; Breizman et al 1997 Phys. Plasmas 4 1559–68; Berk et al 1997 Plasma Phys. Rep. 23 778–88). The fifth-order terms in the wave equation are calculated for the first time, which allow us to quantify this accuracy arbitrarily close to marginal stability. We find a relation between the breakdown of the quantitative accuracy of the cubic equation, occurring well below the instability's saturation level, and the recently observed phase space folding effect (Idouakass 2016 PhD Thesis Aix-Marseille University). This effect emerges when the resonant particle distribution function (Ω is a momentum-like variable, φ is its conjugate variable, and t is the time) evolves from a (locally) single-valued function of φ, at fixed Ω, to a triple-valued one (i.e. there emerges a point in phase space where )
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TAE Saturation of Alpha Particle Driven Instability in TFTR
Get PDFA nonlinear theory of kinetic instabilities near threshold [H.L. Berk, et al., Plasma Phys. Rep. 23, (1997) 842] is applied to calculate the saturation level of Toroidicity-induced Alfvén Eigenmodes (TAE) and be compared with the predictions of (delta)f method calculations [Y. Chen, Ph.D. Thesis, Princeton University, 1998]. Good agreement is observed between the predictions of both methods and the predicted saturation levels are comparable with experimentally measured amplitudes of the TAE oscillations in TFTR [D.J. Grove and D.M. Meade, Nucl. Fusion 25, (1985) 1167]
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Newspaper Clipping: Author Cornwell wants to help solve Civil War mystery
No full textA newspaper clipping of an article titled 'Author Cornwell wants to help solve Civil War mystery', published in an unknown newspaper on February 15, 2006. The article discusses author Patricia Cornwell's interest in donating funds toward studying what happened to the H.L. Hunley, a Confederate submarine that went missing during the Civil War and was rediscovered and excavated in 2000
The Gerber-Shiu expected discounted penalty-reward function under an affine jump-diffusion model.
Get PDFWe provide a unified analytical treatment of first passage problems under an affine state-dependent jump-diffusion model (with drift and volatility depending linearly on the state). Our proposed model, that generalizes several previously studied cases, may be used for example for obtaining probabilities of ruin in the presence of interest rates under the rational investement strategies proposed by Berk & Green (2004)First passage problems; Risk process; Stochastic rates of interest; Ruin with interest; Affine jump-diffusion models; Penalty/reward functions at ruin;
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