Research fields at the Department of Experimental Physics

At the Department of Experimental Physics of JATE, solid state physics, laser-matter interactions and noises appearing in physical systems are in the focus of experimental and theoretical investigations. Our experiments have recently been extended by the examination of phenomena present at high intensities, including the production of certain electomagnetic fields. Besides these areas, we have been doing research into astronomical and methodological fields, too. The high level of scientific research at our department is marked by the considerable number of references and invited lectures given on international conferences, and the intense relationships with domestic and foreign institutes. The department's extensive educational activity is based on its high-level research. Presenting demonstrations and experiments while teaching is one of the characteristic features of our education. In order to preserve and improve this feature, which is partly traditional and partly to satisfy social requirements, during lectures a lot of experiments are performed and special attention is paid to the improvement of our equipment. Students are welcome to work in the laboratories, and even freshmen are encouraged to take part in the Student Researchers Group. The department also takes part in holding postgraduate courses for PhD candidates and teachers. We pay special attention to both research and education. One of our aims is to modernise the curriculum by continuously adding the latest scientific results to it, which is necessary to keep our trainees up-to-date.

Production of Electromagnetic Fields of High Intensity

Processes taking place above the intensity of 10 ad 20 W/cm2 are a new milestone in the study of light-matter interactions, where the inner electric field of the atoms can be neglected. The study of these interactions and the maintenance of the necessary intensities are the central points in modern physical experiments. However, nowadays the production of these intensities seems to be practicable only with laser-based, usually expensive equipment. Due to their short wavelength, minimal optical distortion and subpicosecond pulse duration, the advantage of ultraviolet excimer gas lasers is that highly focused intensities can be produced, while at the same time the energy output, the size and costs can be kept on medium level. There is much prospect of short ultraviolet impulses' being used for surface shaping, as on the one hand due to short pulse duration there is no thermal damage, and on the other hand due to the short wavelength spatial resolution is very good. Its scientific results made the research team internationally respected in the field of high intensity laser physics.
Keywords: Development of high intensity laser systems, experiments with highly focused ultraviolet excimer gas lasers, generation of pulses of subpicosecond duration. Study of interaction of intense electromagnetic fields with matter.

The Laser-Matter Interaction Laboratory

During the recent years we have produced remarkable results in the field of laser-metal oxidation and that of laser-metal deposition. We have determined the kinetic and dynamic features of metal oxidation caused by continuous wave (CW) and pulse-laser irradiation. We have also described the model of laser oxidation, which is in accordance with our experimental results.
Keywords: Laser-metal oxidation and laser-metal deposition, kinetic and dynamic features of metal oxidation caused by continuous wave and pulse-laser irradiation. Nonlinear and chaotic phenomena.

Noise Research

We have results of great importance concerning 1/f noises. Several new models of 1/f noise have been described, and a number of new features of 1/f noise have been discovered. We have come up with outstanding results in connection with theoretical and experimental examinations of noise phenomena appearing in high temperature superconductors. We have also described a new model regarding the examination of electrical degradation of thin film elements. We have performed analogue, numerical and theoretical experiments in the field of stochastic resonance (excitations with 1/f noise). We have grounded the theory of stochastic resonance taking place in non-dynamic systems. We were the first to introduce such a stochastic resonator which is able to increase signal/noise ratio. Our results have significantly contributed to the description and practical usefulness of the phenomenon.
Keywords: Experiments and theories on noise and fluctuations in physical and biological systems. 1/f noise, stochastic resonance, heart rate and blood pressure

Astronomical Researches

On the basis of photoelectric (PM and CCD) mesurements performed in the Szeged Observatory, we have dealt with the astrophysical examination of variable stars. We have calculated the light change periods of pulsating stars and eclipsing binaries with modern mathematical methods. The temporal changes in the features of the light curve (amplitude, period, phase) provides information of great importance concerning the star's structure and evolutionary state. We were among the scientists who first used wavelet transformation to analyse the light variation of semiregular pulsating stars. We have also proved its adventages compared with methods used before. From the periods of the light changes we have deduced the physical features of stars. Based on the cyclic changes in the period we have shown a third component in the case of some eclipsing binaries, and binarity in the case of some pulsating stars. We have taken spectroscopic measures for pulsating stars abroad and we determined the radial velocity variations.
Keywords: CCD photometry and spectroscopy, astrophysical studies of variable stars, time-frequency analysis of light changes. Study of star clusters, astrometry and photometry of minor planets and comets. Gravitational radiation, gravitation theory, cosmology.
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Evaluating the Results of Teaching Physics Working out Methods that Improve Students' Attitude to the Subject

We have done researches including a representative survey of students' attainment of natural sciences. By comparing the results with the statistics of western and oriental countries, we helped to make a real picture of the Hungarian students' knowledge of natural sciences. By working out the ways of how to apply modern technique in education (e.g. computer simulations, developing new experiments and improving the curriculum) we play a very important role in the modernisation of the curriculum and that of the physics teaching methods.
Keywords: Representative survey of students' attainment and knowledge of natural sciences. Modernisation of the curriculum and the physics teaching strategies, development of new experiments in physics education.