Revisiting the anomalous rf field penetration into a warm plasma

Radio frequency waves do not penetrate into a plasma and are damped within it. The electric field of the wave and plasma current are concentrated near the plasma boundary in a skin layer. Electrons can transport the plasma current away from the skin layer due to their thermal motion. As a result, the width of the skin layer increases when electron temperature effects are taken into account. This phenomenon is called anomalous skin effect. The anomalous penetration of the rf electric field occurs not only for transversely propagating to the plasma boundary wave (inductively coupled plasmas) but also for the wave propagating along the plasma boundary (capacitively coupled plasmas). Such anomalous penetration of the rf field modifies the structure of the capacitive sheath. Recent advances in the nonlinear, nonlocal theory of the capacitive sheath are reported. It is shown that separating the electric field profile into exponential and non-exponential parts yields an efficient qualitative and quantitative description of the anomalous skin effect in both inductively and capacitively coupled plasma.Comment: 44 pages, invited paper at "Nonlocal, Collisionless Phenomena in Plasma" worksho

On the principal series of potassium

We revisit the photoabsorption from the ground state of K through the first ionization limit, and provide recommended values for the optical oscillator strengths. The anomaly in the oscillator strength ratio within each doublet is also revisited and compared with both the experimental data available and the relativistic calculations available.Comment: arXiv admin note: text overlap with arXiv:2211.0783

A new model for the structure of the DACs and SACs regions in the Oe and Be stellar atmospheres

In this paper we present a new mathematical model for the density regions where a specific spectral line and its SACs/DACs are created in the Oe and Be stellar atmospheres. In the calculations of final spectral line function we consider that the main reasons of the line broadening are the rotation of the density regions creating the spectral line and its DACs/SACs, as well as the random motions of the ions. This line function is able to reproduce the spectral feature and it enables us to calculate some important physical parameters, such as the rotational, the radial and the random velocities, the Full Width at Half Maximum, the Gaussian deviation, the optical depth, the column density and the absorbed or emitted energy. Additionally, we can calculate the percentage of the contribution of the rotational velocity and the ions' random motions of the DACs/SACs regions to the line broadening. Finally, we present two tests and three short applications of the proposed model.Comment: 9 pages, 5 figures, accepted for publication in PAS

Dynamic positive column in long-gap barrier discharges

A simple analytical model of the barrier discharge in a long gap between opposing plane electrodes is developed. It is shown that the plasma density becomes uniform over large part of the gap in the course of the discharge development, so that one can speak of a formation of a dynamic positive column. The column completely controls the dynamics of the barrier discharge and determines such characteristics as the discharge current, discharge duration, light output, etc. Using the proposed model, all discharge parameters can be easily evaluatedComment: 7 pages, 8 figures; submitted to the Journal of Applied Physic

Lifetime Measurement of the 8s Level in Francium

We measure the lifetime of the 8s level on a magneto-optically trapped sample of ^{210}Fr atoms with time-correlated single-photon counting. The 7P_{1/2} state serves as the resonant intermediate level for two-photon excitation of the 8s level completed with a 1300 nm laser. Analysis of the fluorescence decay through the the 7P_{3/2} level gives 53.30 +- 0.44 ns for the 8s level lifetime.Comment: 4 pages, 4 figure

Essential elements in international contract negotiations

This research examines the interaction of groups in the environment of international contract negotiations. The thesis addresses psychological aspects of negotiation, such as roles of social relationships, egocentrism, motivated illusions and emotion. The thesis examines the role of culture in cross-border negotiations and describes major effects from negotiation definitions, selection of negotiators, protocol, communication, time, risk propensity, group versus individual decision making, and nature of the agreement. Interviews conducted with expert negotiators yielded a set of factors that research participants identified as the most influential in the negotiation process and its outcome. Recommendations are offered in regards to common issues that arise during an international negotiation process. These include: (a) thoroughly preparing for all aspects of the contract; (b) aiming toward mutual gain; (c) planning for alternatives that the other party can accept; (d) expressing disagreements with a polite and non-argumentative manner; (e) adjustment to the degree of formality of the host team; and (f) understanding the other party's authority to commit as well as the decision making structure of the organization it represents. If a negotiator learns to cope with them at a sufficient level, then he/she has enough tools in his/her possession for the purpose of negotiation.http://archive.org/details/essentialelement109452692Approved for public release; distribution is unlimited

Landau Damping and Anomalous Skin Effect in Low-pressure Gas Discharges: Self-consistent Treatment of Collisionless Heating

In low-pressure discharges, where the electron mean free path is larger or comparable with the discharge length, the electron dynamics is essentially nonlocal. Moreover, the electron energy distribution function (EEDF) deviates considerably from a Maxwellian. Therefore, an accurate kinetic description of the low-pressure discharges requires knowledge of the nonlocal conductivity operator and calculation of the non-Maxwellian EEDF. The previous treatments made use of simplifying assumptions: a uniform density profile and a Maxwellian EEDF. In the present study a self-consistent system of equations for the kinetic description of nonlocal, nonuniform, nearly collisionless plasmas of low-pressure discharges is reported. It consists of the nonlocal conductivity operator and the averaged kinetic equation for calculation of the non-Maxwellian EEDF. This system was applied to the calculation of collisionless heating in capacitively and inductively coupled plasmas. In particular, the importance of accounting for the nonuniform plasma density profile for computing the current density profile and the EEDF is demonstrated. The enhancement of collisionless heating due to the bounce resonance between the electron motion in the potential well and the external radio-frequency electric field is investigated. It is shown that a nonlinear and self-consistent treatment is necessary for the correct description of collisionless heating

Automated segmentation of tissue images for computerized IHC analysis

This paper presents two automated methods for the segmentation ofimmunohistochemical tissue images that overcome the limitations of themanual approach aswell as of the existing computerized techniques. The first independent method, based on unsupervised color clustering, recognizes automatically the target cancerous areas in the specimen and disregards the stroma; the second method, based on colors separation and morphological processing, exploits automated segmentation of the nuclear membranes of the cancerous cells. Extensive experimental results on real tissue images demonstrate the accuracy of our techniques compared to manual segmentations; additional experiments show that our techniques are more effective in immunohistochemical images than popular approaches based on supervised learning or active contours. The proposed procedure can be exploited for any applications that require tissues and cells exploration and to perform reliable and standardized measures of the activity of specific proteins involved in multi-factorial genetic pathologie

Optimizing the fast Rydberg quantum gate

The fast phase gate scheme, in which the qubits are atoms confined in sites of an optical lattice, and gate operations are mediated by excitation of Rydberg states, was proposed by Jaksch et al. Phys. Rev. Lett. 85, 2208 (2000). A potential source of decoherence in this system derives from motional heating, which occurs if the ground and Rydberg states of the atom move in different optical lattice potentials. We propose to minimize this effect by choosing the lattice photon frequency \omega so that the ground and Rydberg states have the same frequency-dependent polarizability \alpha(omega). The results are presented for the case of Rb.Comment: 5 pages, submitted to PR