Electron Acceleration in Underdense Plasmas Described with a Classical Effective Theory

An effective theory of laser--plasma based particle acceleration is presented. Here we treated the plasma as a continuous medium with an index of refraction $n_{m}$ in which a single electron propagates. Because of the simplicity of this model, we did not need to perform PIC simulations in order to study the properties of the electron acceleration. We studied the properties of the electron motion due to the Lorentz force and the relativistic equations of motion were numerically solved and analysed. We compared our results to PIC simulations and experimental data. Keywords: Underdense plasma; Electron acceleration; Classical electrodynamics; Relativistic equation of motion; Ultrashort laser pulsesComment: 14 pages, 7 figures. Proceedings to the ECLIM 2014 Conference (Paris). Submitted to Laser and Particle Beams (Cambridge Journals

Interaction of antiproton with helium based on ab-initio calculations

We present ionization cross sections for antiproton and helium collisions based on ab-initio time-dependent coupled channel method. In our calculations a finite basis set of regular helium Coulomb wave packets and Slater function were used. The semiclassical approximation was applied with the time-dependent Coulomb potential to describe the antiproton electron interaction. Three different projectile energies were considered as 10, 50 and 100 keV. We found clear evidence for the formation of the anti-cusp in the differential distributions.Comment: 17 pages and 3*3 figure

Electron Acceleration by a Bichromatic Chirped Laser Pulse in Underdense Plasmas

A theoretical study of laser and plasma based electron acceleration is presented. An effective model has been used, in which the presence of an underdense plasma has been taken account via its index of refraction $n_{m}$. In the confines of this model, the basic phenomena can be studied by numerically solving the classical relativistic equations of motion. The key idea of this paper is the application of chirped, bichromatic laser fields. We investigated the advantages and disadvantages of mixing the second harmonic to the original $\lambda = 800 \, \mathrm{nm}$ wavelength pulse. We performed calculations both for plane wave and Gaussian pulses.Comment: 6 pages, 7 figures. Proceedings to the PIPAMON (2015) conference. Submitted to NIM-B Special Issue (SI:PIPAMON-2015). Accepted for publication: 7th of October, 201

Strategic segmentation: when two monopolies are better than one

In this article we show that the price and the profit of an incumbent firm may increase after a new firm enters its market. Our analysis suggests that a well-established firm after competition emerges on its market might benefit from excluding some consumers from the low- end segment and concentrate only on its loyal consumers. We also find that strategic de-marketing can increase social welfare

Nothing so certain as your anchors? A consumer bias that might lower prices

Anchoring is a well-known decision-making bias: original guesses for a certain question could act as anchors and could influence our final answers. Reference prices - in a similar fashion - can lead to a bias in consumer valuations, and thus consumer demand will be coherent but not one derived from a utility framework. In our paper we investigate the effect of the existence of anchoring on how oligopolistic firms might change their pricing strategy. More specifically, we analyze the effect of anchoring on pricing when differentiated firms compete in Bertrand fashion. We show that if the anchoring effect is smaller than a threshold the average price is lower compared to the no-anchoring case

Vertikális korlátozások - növelik vagy csökkentik a jólétet? Érvek az irodalomból = Vertical constraints - do they increase or reduce welfare? Arguments in the literature

A vertikális korlátozások témaköre a versenypolitika és -szabályozás egyik legfontosabb, de mindenképpen legtöbb vitát generáló területe. A téma magyar irodalma elsősorban elméleti kérdésekkel foglalkozik, mellőzve a konkrét iránymutatásokat a probléma kezelésére. Először röviden bemutatjuk a vertikális korlátozások indokait és hatásmechanizmusát magyarázó teoretikus irodalmat, felsorolva azok hatékonyságnövelő hatását hangsúlyozó érvrendszereket, illetve a versenykorlátozás lehetőségét tárgyaló modelleket is. Ezután bemutatjuk, hogy milyen fontos empirikus vizsgálatokat végeztek ezen elméletek vizsgálatára, és milyen következtetések vonhatóak le a tapasztalatokból. _________ The field of vertical constraints is one of the most important in competition policy and regulation, but one that generates the most debate. Hungarian literature on the subject deals primarily with theoretical questions, refraining from offering specific guidelines for handling the problem. The paper first covers briefly the causes of the vertical constraints and the Hungarian theoretical literature on its effective mechanism, listing the system of arguments that point to its effect of increasing efficiency and the models that discuss the possibility of limiting competition. The paper then presents the major empirical examinations made of these theories and the conclusions drawn from that experience