The phenomena of nonlinear bremsstrahlung absorption and generation of five first odd harmonics are investigated for a plasma photoionized in the Bethe regime of the suppression of the ionization barrier, in which case the velocity distribution of plasma electrons coincides with the distribution of atomic electrons. The partial nonlinear conductivities are obtained. A comparison is made between the features of the absorption and the effectiveness of harmonic generation in two different cases when atomic electrons before ionization are in the ns- or np-states. It was demonstrated that the nonlinear effective collision frequencies (NECF) have unique form in the limit of the high intensity of the pump field. On the other side NECF have the pump field dependencies near their maximum values which are different for the case of s-states and p-states. These dependencies are characterized by especial sealing functions, which give the dependencies on the pump field intensity, the values of the principal quantum number of the pre-excited states of atoms and harmonics numbers.
{"title":"Nonlinear inverse bremsstrahlung and the harmonic generation in a plasma","authors":"V. Silin, P. Silin","doi":"10.1117/12.537452","DOIUrl":"https://doi.org/10.1117/12.537452","url":null,"abstract":"The phenomena of nonlinear bremsstrahlung absorption and generation of five first odd harmonics are investigated for a plasma photoionized in the Bethe regime of the suppression of the ionization barrier, in which case the velocity distribution of plasma electrons coincides with the distribution of atomic electrons. The partial nonlinear conductivities are obtained. A comparison is made between the features of the absorption and the effectiveness of harmonic generation in two different cases when atomic electrons before ionization are in the ns- or np-states. It was demonstrated that the nonlinear effective collision frequencies (NECF) have unique form in the limit of the high intensity of the pump field. On the other side NECF have the pump field dependencies near their maximum values which are different for the case of s-states and p-states. These dependencies are characterized by especial sealing functions, which give the dependencies on the pump field intensity, the values of the principal quantum number of the pre-excited states of atoms and harmonics numbers.","PeriodicalId":340981,"journal":{"name":"European Conference on Laser Interaction with Matter","volume":"58 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2003-12-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130763858","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Xiaodong Yuan, Xiaofeng Wei, Chengcheng Wang, Xinwu Qing, W. Deng, Bin Xu, D. Jiang, Jun Tang, H. Jia
To measure the temperature and density of electronics in laser plasma accurately, two probe laser systems are built on XG-II laser facility. The one, called UV probe laser system, which can provide the UV laser pulse with duration of 30 ps by cascade Raman compressor after fourth harmonic conversion is used for density measurement of laser plasma. The other one, Thomson scattering system, which can provide the 4 ω laser pulse with energy of 3 - 5J, is now routinely operated for electronics temperature diagnostic in laser plasma. It is the first time that the density and temperature of laser plasma are measured directly by probe laser at the same shot.
{"title":"Study on active probe laser system used for laser plasma diagnostic","authors":"Xiaodong Yuan, Xiaofeng Wei, Chengcheng Wang, Xinwu Qing, W. Deng, Bin Xu, D. Jiang, Jun Tang, H. Jia","doi":"10.1117/12.537293","DOIUrl":"https://doi.org/10.1117/12.537293","url":null,"abstract":"To measure the temperature and density of electronics in laser plasma accurately, two probe laser systems are built on XG-II laser facility. The one, called UV probe laser system, which can provide the UV laser pulse with duration of 30 ps by cascade Raman compressor after fourth harmonic conversion is used for density measurement of laser plasma. The other one, Thomson scattering system, which can provide the 4 ω laser pulse with energy of 3 - 5J, is now routinely operated for electronics temperature diagnostic in laser plasma. It is the first time that the density and temperature of laser plasma are measured directly by probe laser at the same shot.","PeriodicalId":340981,"journal":{"name":"European Conference on Laser Interaction with Matter","volume":"196 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2003-12-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123381090","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
V. Zvorykin, V. G. Bakaev, A. Iskakov, I. Lebo, G. Sychugov, V. Tishkin
We have suggested a concept of laser-driven shock tube (LST) for generation of hypersonic shock waves (SW) in gases and compression waves in liquids. This novel laboratory technique might be applied to the studies of various fundamental hydrodynamic phenomena such as development of hydrodynamic instabilities at contact interfaces between different liquids and gases accelerated by shock waves, hypersonic gas flow around bodies, effects of strong shock wave refraction and cumulation in time scale of several microseconds and space scale of ten millimeters. These problems are of great importance in Inertial Confinement Fusion, comsology, astrophysics, and aerospace engineering. In this paper we present both numerical simulations and first experimental results to verify the laser-driven shock tube concept for studying of strong SW generation in the air.
{"title":"GARPUN KrF-laser-target experiments and numerical simulations on the concept of laser-driven shock tube","authors":"V. Zvorykin, V. G. Bakaev, A. Iskakov, I. Lebo, G. Sychugov, V. Tishkin","doi":"10.1117/12.536557","DOIUrl":"https://doi.org/10.1117/12.536557","url":null,"abstract":"We have suggested a concept of laser-driven shock tube (LST) for generation of hypersonic shock waves (SW) in gases and compression waves in liquids. This novel laboratory technique might be applied to the studies of various fundamental hydrodynamic phenomena such as development of hydrodynamic instabilities at contact interfaces between different liquids and gases accelerated by shock waves, hypersonic gas flow around bodies, effects of strong shock wave refraction and cumulation in time scale of several microseconds and space scale of ten millimeters. These problems are of great importance in Inertial Confinement Fusion, comsology, astrophysics, and aerospace engineering. In this paper we present both numerical simulations and first experimental results to verify the laser-driven shock tube concept for studying of strong SW generation in the air.","PeriodicalId":340981,"journal":{"name":"European Conference on Laser Interaction with Matter","volume":"20 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2003-12-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127237887","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Istvan B. Foeldes, K. Gál, G. Kocsis, E. Rácz, S. Szatmári, G. Veres
The generation of high-harmonics in laser-plasma interactions on the steep density gradients is discussed, especially by using short pulse UV laser radiation. Low intensity experiments with 5 • 1015W/cm2 showed high harmonics in the VUV range and the efficiency could be optimized by modifying the density gradient. The disagreement among different experiments and the lack of a full theoretical understanding of the generation mechanism forced us to switch for higher intensities. The experimental arrangement for obtaining 5 • 1017W/cm2 intensity with low-prepulse using a table-top system is shown. Preliminary results and future trends for high-harmonics generation with this method is given.
{"title":"High-harmonics from a UV laser plasma","authors":"Istvan B. Foeldes, K. Gál, G. Kocsis, E. Rácz, S. Szatmári, G. Veres","doi":"10.1117/12.536889","DOIUrl":"https://doi.org/10.1117/12.536889","url":null,"abstract":"The generation of high-harmonics in laser-plasma interactions on the steep density gradients is discussed, especially by using short pulse UV laser radiation. Low intensity experiments with 5 • 1015W/cm2 showed high harmonics in the VUV range and the efficiency could be optimized by modifying the density gradient. The disagreement among different experiments and the lack of a full theoretical understanding of the generation mechanism forced us to switch for higher intensities. The experimental arrangement for obtaining 5 • 1017W/cm2 intensity with low-prepulse using a table-top system is shown. Preliminary results and future trends for high-harmonics generation with this method is given.","PeriodicalId":340981,"journal":{"name":"European Conference on Laser Interaction with Matter","volume":"33 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2003-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133714140","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A. Maksimchuk, V. Bychenkov, K. Flippo, H. Krause, K. Mima, G. Mourou, K. Nemoto, Y. Sentoku, D. Umstadter, R. Vane
We report on multi-MeV ion beam generation from the interaction of a 10 TW, 400 fs, 1.053 μm laser focused onto thin foil targets at intensities ranging from 1017 to 1019 W/cm2. Ion beam characteristics were studied by changing laser intensity, the preformed plasma scale-length and target material initial conductivity. We manipulated the proton beam divergence by using shaped targets. We observed nuclear transformation induced by high-energy protons and deuterons. A fully relativistic two-dimensional particle-in-cell simulation modeled energetic ion generation. These simulations identify the mechanism for the hot electron generation at the laser-plasma interface. Comparison with experiments sheds light on the dependence of ion-energy on preplasma scale length and solid density plasma thickness as well as relates ion energies for multi-species plasma.
{"title":"High-energy ion generation","authors":"A. Maksimchuk, V. Bychenkov, K. Flippo, H. Krause, K. Mima, G. Mourou, K. Nemoto, Y. Sentoku, D. Umstadter, R. Vane","doi":"10.1117/12.536776","DOIUrl":"https://doi.org/10.1117/12.536776","url":null,"abstract":"We report on multi-MeV ion beam generation from the interaction of a 10 TW, 400 fs, 1.053 μm laser focused onto thin foil targets at intensities ranging from 1017 to 1019 W/cm2. Ion beam characteristics were studied by changing laser intensity, the preformed plasma scale-length and target material initial conductivity. We manipulated the proton beam divergence by using shaped targets. We observed nuclear transformation induced by high-energy protons and deuterons. A fully relativistic two-dimensional particle-in-cell simulation modeled energetic ion generation. These simulations identify the mechanism for the hot electron generation at the laser-plasma interface. Comparison with experiments sheds light on the dependence of ion-energy on preplasma scale length and solid density plasma thickness as well as relates ion energies for multi-species plasma.","PeriodicalId":340981,"journal":{"name":"European Conference on Laser Interaction with Matter","volume":"37 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2003-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128574029","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
An experimental study of space-resolved x-ray emission from a laser produced magnesium plasma expanding in a helium gas background has been performed at different gas pressures up to 125 mbar. A strong enhancement in MgXI He-α resonance (1s2 1So - 1s2p 1P1 at 9.17Å) and intercombination (1s2 1So - 1s2p 3P1 at 9.23Å) line emission is observed in the blast wave region extending upto ~6 mm from the target. Results of measurements of pressure dependence of peak x ray line intensity, onset distance, size of the emission region, and intensity ratio of the two lines are described and the role of background gas to explain the observed behavior is discussed. At optimum background pressure of about 40 mbar there is an order of magnitude increase in the x-ray line intensity compared to that for a gas pressure of few mbar. Charge exchange and three body recombination rates have also been analyzed for their relative contribution towards this intensity enhancement.
{"title":"Pressure dependence of enhanced x-ray line emission from laser-produced plasmas expanding in an ambient gas","authors":"A. Chowdhury, V. Arora, P. Naik, P. Gupta","doi":"10.1117/12.535929","DOIUrl":"https://doi.org/10.1117/12.535929","url":null,"abstract":"An experimental study of space-resolved x-ray emission from a laser produced magnesium plasma expanding in a helium gas background has been performed at different gas pressures up to 125 mbar. A strong enhancement in MgXI He-α resonance (1s2 1So - 1s2p 1P1 at 9.17Å) and intercombination (1s2 1So - 1s2p 3P1 at 9.23Å) line emission is observed in the blast wave region extending upto ~6 mm from the target. Results of measurements of pressure dependence of peak x ray line intensity, onset distance, size of the emission region, and intensity ratio of the two lines are described and the role of background gas to explain the observed behavior is discussed. At optimum background pressure of about 40 mbar there is an order of magnitude increase in the x-ray line intensity compared to that for a gas pressure of few mbar. Charge exchange and three body recombination rates have also been analyzed for their relative contribution towards this intensity enhancement.","PeriodicalId":340981,"journal":{"name":"European Conference on Laser Interaction with Matter","volume":"73 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2003-03-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133503732","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
K. Oades, M. Stevenson, G. Slark, L. Suter, M. C. Miller, J. Grun, John F. Davis, R. Kauffman
We report on an extensive series of experiments using 2ω light on a variety of gaseous targets at the HELEN laser facility at AWE. The aims of the experiments were to investigate laser-plasma interactions and hot electron generation for 2ω light, and to test schemes for efficiently producing multi-keV X-rays. The experiments were diagnosed by an extensive suite of optical and x-ray instrumentation, including streaked SRS and SBS spectrographs, hard X-ray and Dante measurements. The targets used to data have been filled with C5H12, CO2 and Kr. These three targets give very different backscatter, including almost no backscatter from the Kr targets, showing that plasma composition can also be used to minimize backscatter losses. These data also indicate that is possible to produce or quench hot electron production by varying the plasma composition, even near quarter critical density.
{"title":"Exploring 2ω laser-plasma interactions on the HELEN laser system","authors":"K. Oades, M. Stevenson, G. Slark, L. Suter, M. C. Miller, J. Grun, John F. Davis, R. Kauffman","doi":"10.1117/12.535908","DOIUrl":"https://doi.org/10.1117/12.535908","url":null,"abstract":"We report on an extensive series of experiments using 2ω light on a variety of gaseous targets at the HELEN laser facility at AWE. The aims of the experiments were to investigate laser-plasma interactions and hot electron generation for 2ω light, and to test schemes for efficiently producing multi-keV X-rays. The experiments were diagnosed by an extensive suite of optical and x-ray instrumentation, including streaked SRS and SBS spectrographs, hard X-ray and Dante measurements. The targets used to data have been filled with C5H12, CO2 and Kr. These three targets give very different backscatter, including almost no backscatter from the Kr targets, showing that plasma composition can also be used to minimize backscatter losses. These data also indicate that is possible to produce or quench hot electron production by varying the plasma composition, even near quarter critical density.","PeriodicalId":340981,"journal":{"name":"European Conference on Laser Interaction with Matter","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129871493","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
V. Malka, F. Amiranoff, C. Chenais-popovics, J. Gauthier, C. Labaune, E. Leboucher-Dalimier, C. Sauteret, A. Migus
Since its creation, LULI has given an important contribution to laser plasma physics and Inertial Confinement Fusion studies. We will review some major results obtained these last two years with a 600 ps laser chain and with the recent 100-TW, 300fs ultra-intense laser chain. These result cover a wide spectrum of laser plasma physics research such as laser plasma interaction, laser plasma acceleration, fast ignitor, atomic processes in dens plasmas, shock waves generation and x-rays laser.
{"title":"Status and overview of research programs at LULI 2000","authors":"V. Malka, F. Amiranoff, C. Chenais-popovics, J. Gauthier, C. Labaune, E. Leboucher-Dalimier, C. Sauteret, A. Migus","doi":"10.1117/12.425548","DOIUrl":"https://doi.org/10.1117/12.425548","url":null,"abstract":"Since its creation, LULI has given an important contribution to laser plasma physics and Inertial Confinement Fusion studies. We will review some major results obtained these last two years with a 600 ps laser chain and with the recent 100-TW, 300fs ultra-intense laser chain. These result cover a wide spectrum of laser plasma physics research such as laser plasma interaction, laser plasma acceleration, fast ignitor, atomic processes in dens plasmas, shock waves generation and x-rays laser.","PeriodicalId":340981,"journal":{"name":"European Conference on Laser Interaction with Matter","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-04-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123402500","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
K. Kuwahara, E. Takahashi, Y. Matsumoto, I. Matsushima, I. Okuda, S. Kato, Y. Owadano
We have developed a new technique for high intensity short pulse generation. It consists of a steep pulse generation and a saturated amplification. Stimulated Brillouin scattering by a broad-band oscillator pulse was used to generate the steep Stokes pulse. The Stokes pulse was amplified by discharge type KrF laser amplifier under strongly saturated condition. The pulse shortening by the amplification was confirmed.
{"title":"High-intensity pulse generation by saturated amplification of Stokes pulse with steep leading edge","authors":"K. Kuwahara, E. Takahashi, Y. Matsumoto, I. Matsushima, I. Okuda, S. Kato, Y. Owadano","doi":"10.1117/12.425582","DOIUrl":"https://doi.org/10.1117/12.425582","url":null,"abstract":"We have developed a new technique for high intensity short pulse generation. It consists of a steep pulse generation and a saturated amplification. Stimulated Brillouin scattering by a broad-band oscillator pulse was used to generate the steep Stokes pulse. The Stokes pulse was amplified by discharge type KrF laser amplifier under strongly saturated condition. The pulse shortening by the amplification was confirmed.","PeriodicalId":340981,"journal":{"name":"European Conference on Laser Interaction with Matter","volume":"6 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-04-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114575192","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A collisional-radiative model has bene developed to calculate the physical and optical characteristics of thermodynamical nonequilibrium plasma. The mean charge of plasma ions, the ionization-state density, radiative energy losses, line ratios, the opacities and the emissivities have been calculated for the steady-state optically transparent plasma, which contains aluminum or copper multi charged ions, in a broad range of plasma densities and temperatures. The comparison shows that our result agree satisfactorily with the calculation results of other authors and with the experimental data.
{"title":"Calculation of optical characteristics of nonequilibrium plasma","authors":"E. Ivanov, V. Rozanov, G. Vergunova","doi":"10.1117/12.425621","DOIUrl":"https://doi.org/10.1117/12.425621","url":null,"abstract":"A collisional-radiative model has bene developed to calculate the physical and optical characteristics of thermodynamical nonequilibrium plasma. The mean charge of plasma ions, the ionization-state density, radiative energy losses, line ratios, the opacities and the emissivities have been calculated for the steady-state optically transparent plasma, which contains aluminum or copper multi charged ions, in a broad range of plasma densities and temperatures. The comparison shows that our result agree satisfactorily with the calculation results of other authors and with the experimental data.","PeriodicalId":340981,"journal":{"name":"European Conference on Laser Interaction with Matter","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-04-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129698750","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
京公网安备 11010802042870号
京ICP备2023020795号-1
扫码关注我们
求助内容：
应助结果提醒方式：