Сurrent problems in energetic materials ignition studies

Several problems of ignition of energetic materials (EMs), which are able to burn in the absence of an external oxidizer, are discussed in this chapter. Scientific investigation of the EMs ignition has started at the end 1930th when the first field missiles (Katyusha) were developed in the USSR. Later the investigations were actively performed in USA and Europe but despite rather long history there still remain unsolved problems related to complete description of nonstationary transition to self-sustaining combustion, correct determination of the ignition moment, determination of the EM high-temperature reaction kinetics, etc. In the early studies, the limiting cases of the EM ignition solely due to exothermic reactions either in the condensed or gas phase were investigated but later it was revealed that formany EMs such reactions can proceed simultaneously in both phases. This implies the necessity of analyzing the ignition mechanisms involving reactions in the condensed as well as in the gas phase. In this chapter, the attention is paid to theoretical description of transient burning rate behavior of the EMs exothermically reacting in both phases, to the formulation of ignition criterion and to the experimental methods of measuring transient burning rate. In addition, the problems of correct determination of the EMs high-temperature kinetics are discussed as well as the problems of ignition of EMs with shielded reacting surface (opaque and semitransparent substances). Obviously, due to restricted volume, the chapter could not answer all questions but its content may become useful for researchers working in this field in order to better understand state of the art of EMs ignition studies and better plan some future researches in this direction

Assessing written work by determining competence to achieve the module-specific learning outcomes.

This chapter describes lasers and other sources of coherent light that operate in a wide wavelength range. First, the general principles for the generation of coherent continuous-wave and pulsed radiation are treated including the interaction of radiation with matter, the properties of optical resonators and their modes as well as such processes as Q-switching and mode-locking. The general introduction is followed by sections on numerous types of lasers, the emphasis being on todayʼs most important sources of coherent light, in particular on solid-state lasers and several types of gas lasers. An important part of the chapter is devoted to the generation of coherent radiation by nonlinear processes with optical parametric oscillators, difference- and sum-frequency generation, and high-order harmonics. Radiation in the extended ultraviolet (EUV) and x-ray ranges can be generated by free electron lasers (FEL) and advanced x-ray sources. Ultrahigh light intensities up to 1021 W/cm2 open the door to studies of relativistic laser–matter interaction and laser particle acceleration. The chapter closes with a section on laser stabilization