| Study on physical mechanism of light flash produced by hypervelocity impact on2A12 Al plate.It has important application value for improving the protection of spacecraft,deep space exploration ability,experimental verification of related objects,the establishment of the anti missile system and the damaged armor weapon.In this paper,the physical mechanism of the flash is studied by theoretical derivation,experiment and numerical simulation.The main results are as follows:1)on the previous’ study on energy allocation during hypervelocity impact,distribution of kinetic energy of projectile hypervelocity impact thick target summary the deformation energy inducting into target energy increasing,impact debris splash energy,produce radiant energy of electromagnetic radiation during projectile hypervelocity impact target plate and projectile and target of stress wave propagation,combining with theoretical analysis,experimental and numerical simulation of impact velocity for 2.61km/s vertical collision energy distribution of 2A12 aluminum target were quantitatively calculated.The study results show that experimental results and theoretical results are derived and numerical simulation results are basically consistent no matter crater morphology,size or radiant temperature.Light flash energy is very few,this experiment is about 0.262 J.2)As the 2A12 Al alloy material,the 93% is the aluminum element,then the flash radiation is mainly aluminum element spectral radiation.In this paper,we have studied the atomic spectra of the 2A12 aluminum target in the process of the collision of 2A12 aluminum target.At the same time,the ultra high speed collision process also appears the plasma vapor cloud,namely the atom has the ionization.Ultra high speed collision of aluminum atoms to produce aluminum,flash radiation also contains ion spectra.On the basis of Bohr theory,the energy levels of the atoms are calculated,and the radiationspectra of the aluminum and the aluminum ions are calculated according to the atomic energy level transition theory.Through the two stage light gas gun loading experiment,using ESA4000 spectrometer to measure the spectral radiant intensity of flash,the characteristics of plasma vapor cloud was measured by Langmuir three probe.The spectrum of flash radiation and the relationship between the degree of ionization and the relationship between the plasma and the plasma are analyzed.Research results show that:a)The energy levels of the Al elements are calculated,and the energy level calculation method proposed by Bohr theory is valid for the Al element.At the same time,the spectra of Al elements are also explored.b)Description around levels of Al atom in the quantum mechanics,electronics are found in the spherical shell in the relative probability of22πr4R with r changed graphics is wave shaped,the electrons in the level and the movement of the near.The probability of the electron in the electron around the atom is the largest,and the probability of the occurrence of electrons around the energy level is small.The probability of the release or absorption of the electron energy level is also varied with the change of the position of the atom.Al element is reflected in the spectrum,that is,the atomic spectrum has a certain width.The conclusion of quantum mechanics is in accord with the experiment.We believe that this theory is more close to the fact that the atom is in fact.c)The experimental results show that with the increase of the speed of the high speed collision,the intensity of the shorter spectrum is increasing rapidly,and the intensity of the long spectral lines is increasing slowly.d)2A12 aluminum projectile with a high speed collision with 2A12 aluminum target produced a plasma,which indicates that the atom has been ionized,which shows that the spectrum of the spectrometer is contained in the light of the aluminum ion.The experimental results show that the electron density of the plasma vapor cloud increases rapidly with the increase of the speed of the high speed impact.However,the electrontemperature of the plasma vapor cloud has little change.In the test,the 2A12 aluminum projectile was 2.75km/s,2.95km/s,3.2km/s,3.3km/s and 30° respectively.The relationship between the maximum electron density of the plasma and the impact velocity is obtained by fitting the parameters of the plasma parameters in the experiment,The fitting result is approximate to:Ne=1.07033×10-17×v9.34226.e)It can be seen that the temperature of the plasma generated by the 2A12 aluminum projectile with a high speed impact on the 2A12 target plate has a great influence on the degree of ionizationD=1.81911×10-38×T9.17024f)2A12 aluminum projectile hypervelocity impact 2A12 aluminum produce plasma,the projectile velocity is 3.30km/s（The incident angle of the projectile is 30°）.Calculation results show: the degree of ionization of atoms is D=5.76×10-5.The ionization of atoms is very small and the content of aluminum ions is small,so the flash radiation intensity of the flash is small,and the experimental results show that the radiation intensity is very small. |
