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The effects induced by microwave field upon tungsten wires of different diameters were investigated. Tungsten wires with 0.5 and 1.0 mm diameters were placed in the focal point of a single-mode cylindrical cavity linked to a microwave generator and exposed to microwave field in ambient air. The experimental results showed that the 0.5 mm diameter wire was completely vaporized due to microwaves strong absorption, while the wire with 1 mm diameter was not ignited. During the interaction between microwaves and tungsten wire with 0.5 mm diameter, a plasma with a high electronic excitation temperature was obtained. The theoretical analysis of the experiment showed that the voltage generated by metallic wires in interaction with microwaves depended on their electric resistance in AC and the power of the microwave field. The physical parameters and dimension of the metallic wire play a crucial role in the ignition process of the plasma by the microwave field. This new and simple method to generate a high-temperature plasma from a metallic wire could have many applications, especially in metal oxides synthesis, metal coatings, or thin film deposition.

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The aim of this research is to understand the plasma initiation process generated by metallic wires when interacting with high energy density microwaves. Lead (Pb) and molybdenum (Mo) wires of 0.5 mm diameter were investigated in this experiment. The end of the metallic wire was placed into the nodal point of a waveguide cavity attached to a microwave generator, where it was exposed to the high energy density of the microwave field. Following the interaction between microwaves and the metallic wire, a plasma was initiated having as effect the wire vaporization. The experiments were conducted in atmospheric air at ~1 bar pressure. From optical emission spectroscopy investigations it was observed that electronic excitation of the plasma has high values and it is in a local thermal equilibrium. The theoretical calculation of the voltages induced in the metallic wires when exposed to high magnitude of the microwave field are similar to those measured in air breakdown experiments. The SEM analysis of the tips of the metallic wires showed that the field effect process is responsible for the ignition of the metallic wires and plasma generation.

The large time of life of 146Sm suggests the possibility to use this p - nuclide as astrophysical chronometer to study the geochemical galactic evolution. Due to the high temperature and large densities of gamma quanta, neutrons and protons in stellar environment 146Sm nucleus can be obtained in (γ,n), (n,2n), (p,2n) processes on 147Sm.The knowledge of corresponding cross sections of gamma rays, neutrons and alpha induced processes is of a great importance for the explanation of (146Sm/144Sm) ratio uncertainties observed on the Earth, meteorites, Moon and other celestial bodies.Cross sections of (γ,n), (n,2n), (α,γ) processes induced by fast gamma rays, neutrons and alphas on 147Sm and 142Nd, from threshold up to 25 MeV were evaluated and predicted in the frame of Hauser-Feshbach statistical model by using Talys software and the own computer programs. For each nuclear reaction contribution of direct, compound and pre-equilibrium mechanisms were determined. Theoretical evaluations are compared with existing experimental data. Parameters of optical potential in the incident and emergent channels and of nuclear densities were extracted. Calculated cross sections together with corresponding nuclear data were used in the evaluation of astrophysical rates necessary in the determination of elemental abundances as needed by nuclear astrophysical networks.