Stage 2 - P1 2017
The project implementation schedule
Phase no. 15
Responsible: Dr. F. Spineanu / (Dr. V. Stancalie / Dr. C. Iorga)
Title: "Transient atomic processes in plasmas generated by intense pulses"
Abstract: We plan to study transient atomic processes and plasma in the parameters range of the hot and dense matter produced at the interaction of an ultra-short and very intense laser pulse. In particular, we study the effects of the intense field on the electronic structure of an ion. These intense fields are present in plasma fusion, plasma astrophysics and laser plasma. In the latter case, they can be produced in two ways: (a) through the non-shielded field of ion charge in plasma, which produces strong coupling effects such as continuum reduction, line width and spectral overlay, or (b) through the electromagnetic field of an intense laser, leading to the formation of satellite lines around the forbidden X-ray lines. Using the Dirac-Fock relativistic method, detailed studies have been carried out to describe the correction to the ionizing energy of an atom under ultra-intensive laser field and the corresponding widths of X-ray lines in the K, L, and M series. We present results from the numerical simulations.
Phase no. 16
Responsible: Dr. F. Jipa/ Dr. M Zamfirescu
Title: "Interacţia pulsurilor laser ultraintense cu micro-ţintele fabricate prin metode foto-litografice"
Phase no. 17
Responsible: Dr. Sandu Ion
Title: "Autoasamblarea unor nanomateriale prin ablatia laser a unor picaturi depuse pe substrat"
Phase no. 18
Responsible: Dr. C. Diplasu
Title: "Probe beam extraction system integrated into the interaction chamber for access to high intensity pulse characterization used in interaction"
Abstract: The CETAL PWser facility run repetition rate and peak power regimes: 10 Hz @ 45 TW and 0.1 Hz @ 1 PW delivering a full aperture size laser beam of 180 mm into the interaction chamber.
The initial control configuration of this laser in both operation regimes was made in “continuous mode” in delivering pulses and associated synchronization electrical signals. An in-house customized synchronization system was implemented to the laser system to work in order to extend the delay generation unit capabilities over shot to shot and burst modes of delivering laser pulses and synchronization signals for the diagnostics devices in the interaction chamber.
While the laser beam spatio-temporal properties can be optimized through the amplification chains of ultra-intense laser systems, the major issues are related to the beam delivery on target, where both spatial and temporal pulse structure are affected by complexity of the beam transport system. From optical compressor the laser beam is traveling under vacuum (10-6 mbar) and the inner diameters pipes are 250 mm which is quite close with beam size. To prevent the beam being clipped on mirrors beam or hitting the tube walls, a system for beam path monitoring and an active alignment system is necessary.
In this sense a semi-automated alignment system has been implemented based on dedicated control software and CCD cameras and using the motorized mounts and is presently used in daily alignment routine of the laser beam in the beam transport system.
Phase no. 19
Responsible: Dr. C. Ticos
Title: "Measurement of the intensity of the relativistic electrons beam accelerated in plasma with a hyperintense laser"
Abstract: An essential part of electron acceleration experiments is the electron beam diagnosis. This phase presents a detailed description of the measuring devices and calibration procedures that allow absolute measurement of the charge of a relativistic electron beam emitted either by laser-plasma interaction or obtained from a linear electron accelerator. By means of independently measured data, a direct cross-calibration of the detection systems used can be made. Three methods for diagnosing the charge of an electron beam: Faraday Cup, Current Integrator Transformer (ICT), and radiochromic film (Gafchromic EBT3) are presented. ICT is used as an absolute tool for measuring electron beam charge without any uncertainty analysis. The signal from this monitoring system can be cross-calibrated to the absolute charge measured using a Faraday cup and a radiochromic film.
Phase no. 20
Responsible: Dr. F. Spineanu
Title: "Plasma current sheets and random accelerated elecron beams"
Abstract: This research is devoted to one of the major themes of the experimental and applicative destination of the Lasers of high power: generation of a beam of high energy ions with an energetic spectrum of reduced dispersion. This beam is meant to be used in connection with nuclear applications. An important obstacle in attaining this goal is the spectrum of the energies of the electron component, which although are dominated by the momentum impulse they have received from the Laser pulse, are subject to instabilities and turbulence. One major problem is the generation of highly accelerated electrons in regions around X points of the reconnections. Since the cuasi-coherent structures that can be formed in plasma are transient we must study their evolution in the „tearing” instability and find, - if possible, the amount of accelerated electrons whose energies are away from the spectrum of energy of the bulk.
We have proposed an explicative structure and we have developed elements of an analytical construction destinated to this objective:
(1) The instability of a current sheet to the “tearing” process, which occurs in the magnetic reconnection
(2) The determination of the shape of the perturbation of the magnetic field during this instability, with the expectation that it will exhibit tendency to filamentation
(3) Calculation of the current of accelerated electrons, which, for an electric field higher than the critical one (Dreicer) are “runaways”.
We propose this explicative structure and its analytical methods to constitute the ground for the study of the quality of generation of a proton beam with narrow energetic width. This approach must be developed and completed with numerical investigations.