A. Knyazkova, Polina V. Shulmina, Y. Kistenev, А. А. Markelov, M. B. Miroshnichenko, A. Borisov
Low-level laser exposure is a non-invasive and less painful method, which is used as an alternative method to classical acupuncture with metal needles and could be applied in clinical medical practice. The study of the laser acupuncture effect on the electroencephalogram (EEG) characteristics was carried out. The electrodes were located on the surface of the subject's head according to the standard scheme 10-20. Experimental EEG data were obtained by standard digital 16-channel electroencephalograph with EEG18 V5.0.3 software. The EEG frequencies in each of the measurements have been analyzed. This work shows that low-level laser stimulation able to change the power of rhythms in the head areas, which corresponds to the stimulation of different brain regions.
{"title":"Influence of laser acupuncture on EEG characteristics","authors":"A. Knyazkova, Polina V. Shulmina, Y. Kistenev, А. А. Markelov, M. B. Miroshnichenko, A. Borisov","doi":"10.1117/12.2550757","DOIUrl":"https://doi.org/10.1117/12.2550757","url":null,"abstract":"Low-level laser exposure is a non-invasive and less painful method, which is used as an alternative method to classical acupuncture with metal needles and could be applied in clinical medical practice. The study of the laser acupuncture effect on the electroencephalogram (EEG) characteristics was carried out. The electrodes were located on the surface of the subject's head according to the standard scheme 10-20. Experimental EEG data were obtained by standard digital 16-channel electroencephalograph with EEG18 V5.0.3 software. The EEG frequencies in each of the measurements have been analyzed. This work shows that low-level laser stimulation able to change the power of rhythms in the head areas, which corresponds to the stimulation of different brain regions.","PeriodicalId":205170,"journal":{"name":"Atomic and Molecular Pulsed Lasers","volume":"24 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-12-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123989035","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}
Stimulated Rayleigh–Mie scattering (SRMS) in two-photon absorption liquids is realized by a Fourier transform-limited pulsed Nd-glass laser. For the first time, we have measured anti-Stokes spectral shifts of SRMS in toluene and hexane colloids of Ag nanoparticles, as well as in pure toluene. The suspensions are prepared in the plasma discharge excited in a liquid exposed to an intense ultrasonic field above the cavitation threshold. This novel technique has been developed for the synthesis of various nano-sized materials; it provides silver nanoparticles suspensions with controlled narrow distribution of the particle size. Ultrasonic cavitation results in a drastic change in the physical properties of the liquid, providing specific conditions in the electrical discharge plasma. Ag nanoparticles with 1-2 nm radii in toluene and hexane are obtained from silver electrodes under these specific conditions and acquire unique surface characteristics which prevent them from secondary agglomeration. The values of anti-Stokes spectral shifts of SRMS appreciably exceed the Rayleigh line width in those liquids. The four-wave mixing method is applied both experimentally and theoretically to display the process as Rayleigh-induced parametric generation. We show that the amplification effect is provided predominantly by thermally induced coherent polarization oscillations, while an interference-assisted thermal grating provides formation of a self-induced optical cavity inside the interaction region.
{"title":"A comparative study of anti-Stokes shift under stimulated Rayleigh-Mie scattering in suspensions of Ag nanoparticles obtained in plasma discharge in liquid under ultrasonic cavitation","authors":"N. Bulychev, A. Erokhin, M. Kazaryan","doi":"10.1117/12.2550775","DOIUrl":"https://doi.org/10.1117/12.2550775","url":null,"abstract":"Stimulated Rayleigh–Mie scattering (SRMS) in two-photon absorption liquids is realized by a Fourier transform-limited pulsed Nd-glass laser. For the first time, we have measured anti-Stokes spectral shifts of SRMS in toluene and hexane colloids of Ag nanoparticles, as well as in pure toluene. The suspensions are prepared in the plasma discharge excited in a liquid exposed to an intense ultrasonic field above the cavitation threshold. This novel technique has been developed for the synthesis of various nano-sized materials; it provides silver nanoparticles suspensions with controlled narrow distribution of the particle size. Ultrasonic cavitation results in a drastic change in the physical properties of the liquid, providing specific conditions in the electrical discharge plasma. Ag nanoparticles with 1-2 nm radii in toluene and hexane are obtained from silver electrodes under these specific conditions and acquire unique surface characteristics which prevent them from secondary agglomeration. The values of anti-Stokes spectral shifts of SRMS appreciably exceed the Rayleigh line width in those liquids. The four-wave mixing method is applied both experimentally and theoretically to display the process as Rayleigh-induced parametric generation. We show that the amplification effect is provided predominantly by thermally induced coherent polarization oscillations, while an interference-assisted thermal grating provides formation of a self-induced optical cavity inside the interaction region.","PeriodicalId":205170,"journal":{"name":"Atomic and Molecular Pulsed Lasers","volume":"23 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-12-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124351197","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}
Features of compression of large-aperture negatively chirped amplified pulses of various aperture and durations up to a few-cycle in IR spectral regions are analyzed. Using the modified ray-tracing algorithm, the spectral-angular dependences of the radiation at different points of the beam cross section at the outputs of the grating compressors constructed according to the Offner, Martinez scheme and the scheme with a single-lens internal telescope are calculated. Offner compressor scheme has minimal aberrations and introduces a spectral angular chirp with a divergence much lower than the beam diffraction divergence. It was shown that in the region of 1.4 μm, negatively chirped pulses can be compressed down to near bandwidth limited duration of ~30 fs over the entire 40 mm beam aperture. It was also shown that, using stretchers with an internal telescope based on the Offner scheme, in the region of 3.6 μm it is possible to compress amplified negatively chirped pulses with duration of 40 ps and with a spectrum width close to an octave down to near bandwidth-limited duration of 18 fs duration at a 20 mm aperture.
{"title":"Compressors of negatively chirped pulses with internal telescope","authors":"D. Shvydkoy, V. Trunov","doi":"10.1117/12.2553210","DOIUrl":"https://doi.org/10.1117/12.2553210","url":null,"abstract":"Features of compression of large-aperture negatively chirped amplified pulses of various aperture and durations up to a few-cycle in IR spectral regions are analyzed. Using the modified ray-tracing algorithm, the spectral-angular dependences of the radiation at different points of the beam cross section at the outputs of the grating compressors constructed according to the Offner, Martinez scheme and the scheme with a single-lens internal telescope are calculated. Offner compressor scheme has minimal aberrations and introduces a spectral angular chirp with a divergence much lower than the beam diffraction divergence. It was shown that in the region of 1.4 μm, negatively chirped pulses can be compressed down to near bandwidth limited duration of ~30 fs over the entire 40 mm beam aperture. It was also shown that, using stretchers with an internal telescope based on the Offner scheme, in the region of 3.6 μm it is possible to compress amplified negatively chirped pulses with duration of 40 ps and with a spectrum width close to an octave down to near bandwidth-limited duration of 18 fs duration at a 20 mm aperture.","PeriodicalId":205170,"journal":{"name":"Atomic and Molecular Pulsed Lasers","volume":"26 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-12-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124979282","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. P. Dresvyanskiy, A. Kuznetsov, S. Enkhbat, O. Bukhtsooj, N. Bobina, S. Alekseev, V. Losev, E. F. Martynovich
The paper presents the results of experimental and theoretical studies of the role of avalanche ionization in the process of highly nonlinear generation of electron-hole pairs in the interaction of intense femtosecond laser radiation with dosimetric crystals LiF:Mg,Ti. We assume that the effective formation of defects of hole-interstitial type, which consist of molecular halogen ions placed in one cationic and two anionic vacancies, distinguished by high-temperature peaks in the thermally stimulated luminescence curves, is feasibly connected with avalanche ionization processes occurring in the regions of passage of light filaments. The calculated dependences of the plasma density on time during the laser pulse made with taking into account the avalanche ionization for this type of crystals show that the contribution of avalanche ionization to the electron-hole plasma density is comparable to that of the multiphoton tunneling mechanism.
{"title":"The role of avalanche ionization in generation of defects in lithium fluoride crystals under the action of femtosecond laser pulses","authors":"V. P. Dresvyanskiy, A. Kuznetsov, S. Enkhbat, O. Bukhtsooj, N. Bobina, S. Alekseev, V. Losev, E. F. Martynovich","doi":"10.1117/12.2554180","DOIUrl":"https://doi.org/10.1117/12.2554180","url":null,"abstract":"The paper presents the results of experimental and theoretical studies of the role of avalanche ionization in the process of highly nonlinear generation of electron-hole pairs in the interaction of intense femtosecond laser radiation with dosimetric crystals LiF:Mg,Ti. We assume that the effective formation of defects of hole-interstitial type, which consist of molecular halogen ions placed in one cationic and two anionic vacancies, distinguished by high-temperature peaks in the thermally stimulated luminescence curves, is feasibly connected with avalanche ionization processes occurring in the regions of passage of light filaments. The calculated dependences of the plasma density on time during the laser pulse made with taking into account the avalanche ionization for this type of crystals show that the contribution of avalanche ionization to the electron-hole plasma density is comparable to that of the multiphoton tunneling mechanism.","PeriodicalId":205170,"journal":{"name":"Atomic and Molecular Pulsed Lasers","volume":"40 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-12-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128336383","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}
I. Shamanin, M. Kazaryan, S. Bedenko, V. Knyshev, V. Shamanin
The possibility of transformation of energy of fast and epithermal neutrons to energy of coherent photon radiation at the expense of a neutron pumping of the active medium formed by nucleus with long-living isomerous states is theoretically described. The channel of the nucleus formation in isomeric state as a daughter nucleus resulting from the nuclear reaction of neutron capture by a lighter nucleus is taken into consideration for the first time. The analysis of cross sections dependence of radiative neutron capture by the nuclei of gadolinium isotopes Gd155 and Gd156 is performed. As a result, it is stated that the speed of Gd156 nuclei formation exceeds the speed of their “burnup” in the neutron flux. It is provided by a unique combination of absorbing properties of two isotopes of gadolinium Gd155 and Gd156 in both thermal and resonance regions of neutron energy. The possibility of excess energy accumulation in the participating medium created by the nuclei of the pair of gadolinium isotopes Gd155 and Gd156 due to formation and storage of nuclei in isomeric state at radiative neutron capture by the nuclei of the stable isotope with a smaller mass is shown. It is concluded that when the active medium created by gadolinium nuclei is pumped by neutrons with the flux density of the order of 1013 cm-2·s-1, the condition of levels population inversion can be achieved in a few tens of seconds. The wave length of the radiation generated by the medium is 0.0006 nm.
{"title":"Dynamics of population of gadolinium-156 nuclei energy levels during neutron pumping of isotope-modified gadolinium oxide","authors":"I. Shamanin, M. Kazaryan, S. Bedenko, V. Knyshev, V. Shamanin","doi":"10.1117/12.2550338","DOIUrl":"https://doi.org/10.1117/12.2550338","url":null,"abstract":"The possibility of transformation of energy of fast and epithermal neutrons to energy of coherent photon radiation at the expense of a neutron pumping of the active medium formed by nucleus with long-living isomerous states is theoretically described. The channel of the nucleus formation in isomeric state as a daughter nucleus resulting from the nuclear reaction of neutron capture by a lighter nucleus is taken into consideration for the first time. The analysis of cross sections dependence of radiative neutron capture by the nuclei of gadolinium isotopes Gd155 and Gd156 is performed. As a result, it is stated that the speed of Gd156 nuclei formation exceeds the speed of their “burnup” in the neutron flux. It is provided by a unique combination of absorbing properties of two isotopes of gadolinium Gd155 and Gd156 in both thermal and resonance regions of neutron energy. The possibility of excess energy accumulation in the participating medium created by the nuclei of the pair of gadolinium isotopes Gd155 and Gd156 due to formation and storage of nuclei in isomeric state at radiative neutron capture by the nuclei of the stable isotope with a smaller mass is shown. It is concluded that when the active medium created by gadolinium nuclei is pumped by neutrons with the flux density of the order of 1013 cm-2·s-1, the condition of levels population inversion can be achieved in a few tens of seconds. The wave length of the radiation generated by the medium is 0.0006 nm.","PeriodicalId":205170,"journal":{"name":"Atomic and Molecular Pulsed Lasers","volume":"8 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-12-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124496329","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. Pashayev, B. Tagiyev, O. B. Tagiyev, K. Allahverdiyev, I. Huseynov, I. Sadikhov
A wide range of rare earth doped crystals used as a lasing media includes: Y3Al5O12 (YAG); Al2O3 (sapphire); chalcogenides of ZnS, ZnSe; sesquioxides of Y2O3, Sc2O3 and others. Ternary thiogallate compounds with common formula AIIB23C4 6 (where A is: Ca, Sr, Ba; B is: Ga, Al; C is- S, Se, Te) consider as a perspective class of chalcogenide semiconductors revealing bright luminescence and laser oscillation properties when doped with rare-earth elements (Eu2+, Nd3+ , Ce3+ etc). In the present research, optical properties and observed laser oscillation of transparent ternary chalcogenide crystals of CaGa2S4 and CaGa2Se4 grown by the chemical vapor transport reaction and doped with Eu2+ (1.0-5.0 a t%) are described. The first observation of laser oscillation from a single crystal CaGa2S4 : Eu2+ (1.0-5.0 at%) have been reported earlier, and for CaGa2Se4 : Eu2+ it is reported for the first time in the present article. The life time of the excited state 4f65d of Eu2+ ions in both crystals determined from the luminescence decay kinetics was ~3.8 μsec. It is shown that photoluminescence maximum in both crystals CaGa2S4 : Eu2+ and CaGa2Se4 : Eu2+ is due to the intra shell transition 4f65d – 4f7(8S7/2) ions.
{"title":"Growth and investigation of optical properties and laser oscillations from ternary thiogallate crystals with laser active dopants","authors":"A. Pashayev, B. Tagiyev, O. B. Tagiyev, K. Allahverdiyev, I. Huseynov, I. Sadikhov","doi":"10.1117/12.2542947","DOIUrl":"https://doi.org/10.1117/12.2542947","url":null,"abstract":"A wide range of rare earth doped crystals used as a lasing media includes: Y3Al5O12 (YAG); Al2O3 (sapphire); chalcogenides of ZnS, ZnSe; sesquioxides of Y2O3, Sc2O3 and others. Ternary thiogallate compounds with common formula AIIB23C4 6 (where A is: Ca, Sr, Ba; B is: Ga, Al; C is- S, Se, Te) consider as a perspective class of chalcogenide semiconductors revealing bright luminescence and laser oscillation properties when doped with rare-earth elements (Eu2+, Nd3+ , Ce3+ etc). In the present research, optical properties and observed laser oscillation of transparent ternary chalcogenide crystals of CaGa2S4 and CaGa2Se4 grown by the chemical vapor transport reaction and doped with Eu2+ (1.0-5.0 a t%) are described. The first observation of laser oscillation from a single crystal CaGa2S4 : Eu2+ (1.0-5.0 at%) have been reported earlier, and for CaGa2Se4 : Eu2+ it is reported for the first time in the present article. The life time of the excited state 4f65d of Eu2+ ions in both crystals determined from the luminescence decay kinetics was ~3.8 μsec. It is shown that photoluminescence maximum in both crystals CaGa2S4 : Eu2+ and CaGa2Se4 : Eu2+ is due to the intra shell transition 4f65d – 4f7(8S7/2) ions.","PeriodicalId":205170,"journal":{"name":"Atomic and Molecular Pulsed Lasers","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-12-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125569643","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. Nizamutdinov, T. A. Telegina, A. A. Buglak, E. Lukinova, E. Madirov, Yuliya L. Vechtomova, M. S. Kritsky, V. Semashko
Melanogenesis disorder leads to several pathologies, including vitiligo. Tetrahydrobiopterin (H4Bip) as the phenylalanine 4-hydroxylase coenzyme catalyzes the oxidation of phenylalanine to tyrosine (a melanin precursor). H4Bip is easily oxidized by oxygen in vivo and in vitro. Vitiligo is accompanied by three-fivefold increased de-novo synthesis of H4Bip, its excess and its further oxidation are essential factors in the pathogenesis of vitiligo. We have demonstrated that pterin products of H4Bip autoxidation (dihydropterin (H2Ptr), dihydroxanthopterin and pterin) predominate over biopterin products (dihydrobiopterin (H2Bip) and biopterin). It was shown that ultraviolet (UV) irradiation accelerates the autoxidation while the products of oxidative degradation of H4Bip act as photosensitizers. Photosensitized oxidation of H4Bip can contribute to the pathogenesis of vitiligo. The main distinguishing feature of UV photooxidation of H4Bip from autoxidation was the formation of dihydropterin (Н2Ptr)2 and dihydrobiopterin (Н2Bip)2 dimers. Here we reported on the dependences of the photodimerization reaction on the wavelength and intensity of radiation using xenon lamps and UV tunable lasers as sources of UV radiation. It was shown that UV irradiation with a laser is more efficient than that with xenon lamp. It was established that the greatest number of dimers were formed by irradiating the H4Bip solution by radiation with a wavelength in the range 308-312 nm. The data obtained are discussed in the context of UVB narrowband vitiligo phototherapy.
{"title":"The role of photochemical transformations of tetrahydrobiopterin in the pathogenesis and phototherapy of vitiligo","authors":"A. Nizamutdinov, T. A. Telegina, A. A. Buglak, E. Lukinova, E. Madirov, Yuliya L. Vechtomova, M. S. Kritsky, V. Semashko","doi":"10.1117/12.2555041","DOIUrl":"https://doi.org/10.1117/12.2555041","url":null,"abstract":"Melanogenesis disorder leads to several pathologies, including vitiligo. Tetrahydrobiopterin (H4Bip) as the phenylalanine 4-hydroxylase coenzyme catalyzes the oxidation of phenylalanine to tyrosine (a melanin precursor). H4Bip is easily oxidized by oxygen in vivo and in vitro. Vitiligo is accompanied by three-fivefold increased de-novo synthesis of H4Bip, its excess and its further oxidation are essential factors in the pathogenesis of vitiligo. We have demonstrated that pterin products of H4Bip autoxidation (dihydropterin (H2Ptr), dihydroxanthopterin and pterin) predominate over biopterin products (dihydrobiopterin (H2Bip) and biopterin). It was shown that ultraviolet (UV) irradiation accelerates the autoxidation while the products of oxidative degradation of H4Bip act as photosensitizers. Photosensitized oxidation of H4Bip can contribute to the pathogenesis of vitiligo. The main distinguishing feature of UV photooxidation of H4Bip from autoxidation was the formation of dihydropterin (Н2Ptr)2 and dihydrobiopterin (Н2Bip)2 dimers. Here we reported on the dependences of the photodimerization reaction on the wavelength and intensity of radiation using xenon lamps and UV tunable lasers as sources of UV radiation. It was shown that UV irradiation with a laser is more efficient than that with xenon lamp. It was established that the greatest number of dimers were formed by irradiating the H4Bip solution by radiation with a wavelength in the range 308-312 nm. The data obtained are discussed in the context of UVB narrowband vitiligo phototherapy.","PeriodicalId":205170,"journal":{"name":"Atomic and Molecular Pulsed Lasers","volume":"12 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-12-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126390927","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}
The efficiency of a real heat engines is considered. Basing on the entropy production minimum principle it is shown that the maximum efficiency of such a machine with an optimum power is n= 1-√T2/T1 defined by the root dependence of cooler and heater temperatures. This disappointing result was obtained earlier for the optimizing the power of Carnot cycle. In this paper we derive aforementioned expression from more general conditions. And we show that it is could be applicable to describe global changes in living and nonliving nature.
{"title":"Some aspects of optimizing the power of a real heat engine","authors":"A. E. Roshdestvensky, A. Erokhin, M. Kazaryan","doi":"10.1117/12.2550619","DOIUrl":"https://doi.org/10.1117/12.2550619","url":null,"abstract":"The efficiency of a real heat engines is considered. Basing on the entropy production minimum principle it is shown that the maximum efficiency of such a machine with an optimum power is n= 1-√T2/T1 defined by the root dependence of cooler and heater temperatures. This disappointing result was obtained earlier for the optimizing the power of Carnot cycle. In this paper we derive aforementioned expression from more general conditions. And we show that it is could be applicable to describe global changes in living and nonliving nature.","PeriodicalId":205170,"journal":{"name":"Atomic and Molecular Pulsed Lasers","volume":"13 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-12-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131412598","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}
E. Sosnin, E. Baksht, V. Kuznetsov, V. Panarin, D. Pechenitsin, V. Skakun, V. Tarasenko
The paper demonstrates the possibility of studying blue jets in laboratory apokamp discharges as a source of blue streamers that move upward from the discharge channel. Research data are presented on the formation of such streamers in low-pressure air at a voltage of tens of kilovolts, showing for the first time that they do arise at low (∼8 Hz) pulse repetition frequencies under pressures at which gigantic blue jets develop 10–20 km above the Earth. At a voltage of positive polarity with an amplitude of 33 kV, the streamer velocity in a pulsed apokamp discharge reaches 560 km/s. When applying microsecond voltage pulses of amplitude 15 kV with a repetition frequency of 50 kHz, the length of streamers ranges to more than 120 cm.
{"title":"Apokamp discharge as a laboratory analogue of the transient luminous events of middle atmosphere","authors":"E. Sosnin, E. Baksht, V. Kuznetsov, V. Panarin, D. Pechenitsin, V. Skakun, V. Tarasenko","doi":"10.1117/12.2541527","DOIUrl":"https://doi.org/10.1117/12.2541527","url":null,"abstract":"The paper demonstrates the possibility of studying blue jets in laboratory apokamp discharges as a source of blue streamers that move upward from the discharge channel. Research data are presented on the formation of such streamers in low-pressure air at a voltage of tens of kilovolts, showing for the first time that they do arise at low (∼8 Hz) pulse repetition frequencies under pressures at which gigantic blue jets develop 10–20 km above the Earth. At a voltage of positive polarity with an amplitude of 33 kV, the streamer velocity in a pulsed apokamp discharge reaches 560 km/s. When applying microsecond voltage pulses of amplitude 15 kV with a repetition frequency of 50 kHz, the length of streamers ranges to more than 120 cm.","PeriodicalId":205170,"journal":{"name":"Atomic and Molecular Pulsed Lasers","volume":"32 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-12-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122607789","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}
The article proposes a design of sensor of optical distortions in a wide field of view for the adaptive optical system of the Large Solar Vacuum Telescope. The calculation of the optical scheme of the sensor based on the use of two wavefront sensors was performed. The working field of view of the adaptive system with an additional sensor for determining the distortions of the wavefront is 120 arc sec. Adjusting the field of view of each Shack-Hartmann sensor up to 30 arc sec is provided by field diaphragms. It is shown that for the used second imager, the quality of subimages remains high, the standard deviation is λ /80.
{"title":"Sensor to register the optical distortions in the wide field of view of solar telescope","authors":"A. Shikhovtsev, S. Chuprakov, P. Kovadlo","doi":"10.1117/12.2553045","DOIUrl":"https://doi.org/10.1117/12.2553045","url":null,"abstract":"The article proposes a design of sensor of optical distortions in a wide field of view for the adaptive optical system of the Large Solar Vacuum Telescope. The calculation of the optical scheme of the sensor based on the use of two wavefront sensors was performed. The working field of view of the adaptive system with an additional sensor for determining the distortions of the wavefront is 120 arc sec. Adjusting the field of view of each Shack-Hartmann sensor up to 30 arc sec is provided by field diaphragms. It is shown that for the used second imager, the quality of subimages remains high, the standard deviation is λ /80.","PeriodicalId":205170,"journal":{"name":"Atomic and Molecular Pulsed Lasers","volume":"394 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-12-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122858502","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}
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