K-shell radiation of projectile ions and solid media during its interaction has been investigated... more K-shell radiation of projectile ions and solid media during its interaction has been investigated. The target media are transparent for radiation applied for diagnostics, which provides the data acquisition directly from the interaction volume. The projectile and target spectra in the energy range of 1.5^ -^ 8 keV were registered by spherically bend crystal spectrometers (FSSR) with a high spatial resolution along the beam propagation. The Ni, Ca and Mg ions accelerated in GSI UNILAC facility to the energies of 11.4 MeV/u were slowed down in quartz and aluminum media. Low-density (up to 0.02 g/cc) quartz aerogel targets allowed expanding 100 times the interaction volume and to determine the evolution of ion beam velocity and charge states inside the media. At the same time, the wavelengths and relative intensities of Kalpha satellite lines radiated by Si and Al target ions with different charges were measured. This has been provided us to investigate the excited media of the heavy i...
ABSTRACT K-shell radiation of fast heavy ions penetrating solid matter was used to analyze the st... more ABSTRACT K-shell radiation of fast heavy ions penetrating solid matter was used to analyze the stopping dynamics of ions over more than 80% of the stopping path. The most important advantage of this method is that the data is obtained with a high spatial resolution directly from the interaction volume. In experiments 11.4 MeV/u Ca projectile were slowed down in solid quartz and low-density SiO{sub 2} aerogel targets. Characteristic projectile and target spectra in the photon energy range of 1.5-4 keV were registered by means of spherically bent crystal spectrometers with high spectral and spatial resolution in the direction of the ion beam propagation. K-shell spectra of heavy ions induced by close collisions with target atoms provided information about the projectile charge state and velocity dynamics. The line intensity distribution of the K-shell transitions arising from ions with different ion charges represents the charge state distribution along the ion beam track. The variation of the line Doppler shift due to the ion deceleration in the target material was used to determine the ion velocity dynamics. The spectroscopic analysis of the stopping process was complemented by measurements of the energy loss and ion charge state distribution after the ion beam emerged from the target using a standard time-of-flight method and magnet spectrometer.
2008 Conference on Lasers and Electro-Optics, 2008
ABSTRACT We found that snow nanotubes targets absorb more than 95% of the incident light of a hig... more ABSTRACT We found that snow nanotubes targets absorb more than 95% of the incident light of a high power laser. Fast ions were generated with energies up to 100keV.
A plasma model of relaxation of a medium in heavy ion tracks in condensed matter is proposed. The... more A plasma model of relaxation of a medium in heavy ion tracks in condensed matter is proposed. The model is based on three assumptions: the Maxwell distribution of plasma electrons, localization of plasma inside the track nanochannel and constant values of the plasma electron density and temperature during the X-ray irradiation. It is demonstrated that the plasma relaxation model adequately describes the X-ray spectra observed upon interaction of a fast ion with condensed target. Preassumptions of plasma relaxation model are validated by the molecular dynamics modeling and simulation.
ABSTRACT X-ray production from the interaction of femtosecond laser pulses focused to relativisti... more ABSTRACT X-ray production from the interaction of femtosecond laser pulses focused to relativistic intensity into re-entrant targets etched into silicon has been investigated. K(alpha) and hard x-ray yields were compared when the laser was focused into pyramidal shaped cone targets and wedge shaped targets. Hot electron production is highest in the wedge targets irradiated with transverse polarization, though K(alpha) is maximized with wedge targets and parallel polarization. These results are explained with particle-in-cell simulations. (c) 2008 American Institute of Physics.
Journal of Physics A: Mathematical and General, 2006
ABSTRACT In this paper, we present experimental results on the excitation of solid-state matter b... more ABSTRACT In this paper, we present experimental results on the excitation of solid-state matter by single, energetic heavy ions. The method of x-ray spectroscopy with spatial resolution along the projectile stopping path inside solids was applied to investigate the state of the medium inside the area of heavy-ion tracks. Spectral data of quartz and aluminium media excited by Ni, Ca and Mg ions from the GSI UNILAC accelerator are presented. The ions' initial energies of 11.4 and 5.9 MeV/u and the beam current on the target in the order of 1 µA were chosen. The observation was focused on relative intensities of Kα satellite lines radiated by Si and Al multicharged ions with different charges. The aerogel medium with extremely low bulk density (0.04 g cc−1) was used to investigate the evolution of target media radiation properties during the projectile ions' stopping and, respectively, the change of the ion's energy deposition into the solids. Due to very short lifetimes of the excited levels for the observed multicharged ions, the data for heavy-ion track area were obtained on tens of femtoseconds time scale after excitation. For further analysis and obtaining quantitative description of heavy-ion track parameters, the methods of numerical simulation are suggested.
X-ray emission and possibility of obtaining radiography images with laser plasma X-ray source ope... more X-ray emission and possibility of obtaining radiography images with laser plasma X-ray source operating at atmospheric pressure and room temperature is investigated. Table top 40 fs 100 uJ laser and Cu and Fe bulk metal targets were used to produce X-ray emission in spectral range of 3-10 keV. The spectra, yield and size of X-ray source were measured under different experimental conditions. X-ray photons of up to 10 keV energy are produced effectively even by relatively low laser intensity < 1015 W/cm2. The source is applied for absorption imaging provided the sensitivity on 10 mum sample thickness and 30 mum spatial resolution of microstructures. The ability to perform phase contrast measurements is demonstrated. The advantages of the proposed method are in smart setup of investigated object within air environment; spectral range tunability; and sensitivity to low-contrast or micron thin details.
A novel type of submicron ion radiography designed to image low-contrast objects, including nanof... more A novel type of submicron ion radiography designed to image low-contrast objects, including nanofoils, membranes and biological structures, is proposed. It is based on femtosecond-laser-driven-cluster-plasma source of multicharged ions and polymer dosimeter film CR-39. The intense isotropic ion flow was produced by femtosecond Ti:Sa laser pulses with intensity ∼ 4x10 17 W/cm 2 absorbed in the supersonic jet of the mixed He and CO2 gases. Two Focusing Spectrometers with Spatial Resolution (FSSR) were used to measure X-ray spectra of H-and He-like multicharged oxygen ions. The spectra testify that ions with energy more than 300 keV were radiated in different directions from the plasma source. High contrast ion radiography images were obtained for 2000 dpi metal mesh, 1 μm polypropylene and 100 nm Zr foils as well as for the different biological objects. Images were recorded on a 1 mm thick CR-39 detector, placed in contact with back surface of the imaged samples at the distances 140 -160 mm from the ion source. The spatial resolution of the image no worse than 600 nm was provided. A difference in object thickness of 100 nm was very well resolved for both Zr and polymer foils. The ion radiography images recorded at different angles from the source, demonstrated almost uniform spatial distribution of ion with total number of 10 8 per shot.
A plasma model for relaxation of a medium in heavy ion tracks in condensed matter is proposed. Th... more A plasma model for relaxation of a medium in heavy ion tracks in condensed matter is proposed. The model is based on three assumptions: the Maxwell distribution of plasma electrons, localization of plasma inside the track nanochannel, and constant values of the plasma electron density and temperature during the X-ray irradiation. It is demonstrated that the plasma relaxation model adequately describes the X-ray spectra observed upon interaction of a fast ion with condensed target. Preassumptions of plasma relaxation model are validated by the molecular dynamics modeling and simulation.
ABSTRACT Hard x rays are generated in laminar helium flow in atmosphere (without a vacuum vessel)... more ABSTRACT Hard x rays are generated in laminar helium flow in atmosphere (without a vacuum vessel) through the interaction of tightly focused 35 fs laser pulses of varying energy with a Cu target. The energy conversion efficiency from laser to K alpha x rays is measured to be 5.4x10(-6), giving a flux of 5.9x10(9) photons/s into 2 pi sr from a source measuring approximately 9x12 mu m(2) in size (verticalxhorizontal). Results are compared to those measured in vacuum and in static helium environments. (c) 2008 American Institute of Physics.
The short review on the possible applications of the hollow ion spectra for the diagnostics of th... more The short review on the possible applications of the hollow ion spectra for the diagnostics of the high-temperature plasma created by intensive laser and particle beams is presented. Because of the hollow ion spectra features are defined mainly by the mechanisms of their excitation, we consider the various types of the high-temperature plasma where different excitation processes are important. It is shown that like ordinary spectral lines, spectra of the hollow ions offer considerable diagnostic opportunities. At the present time, hollow ion spectra are used mainly to investigate plasma heated by X-ray radiation, but the hollow ions must be generated when plasma is heated by fast heavy ion beams too. In this case, the resultant substance state will be also characterized by solid-state density, and some spatial regions of targets will have relatively low temperatures, i.e., will be a nonideal plasma. It is emphasized that hollow ion spectra are promising diagnostic tool for both nonideal plasma and warm dense matter.
Although bipolar jets are seen emerging from a wide variety of astrophysical systems, the issue o... more Although bipolar jets are seen emerging from a wide variety of astrophysical systems, the issue of their formation and morphology beyond their launching is still under study. Our scaled laboratory experiments, representative of young stellar object outflows, reveal that stable and narrow collimation of the entire flow can result from the presence of a poloidal magnetic field whose strength is consistent with observations.The laboratory plasma becomes focused with an interior cavity.This gives rise to a standing conical shock from which the jet emerges. Following simulations of the process at the full astrophysical scale,we conclude that it can also explain recently discovered x-ray emission features observed in low-density regions at the base of protostellar jets, such as the well-studied jet HH 154.
We report the experimental results of a turbulent electric field driven by Kelvin-Helmholtz insta... more We report the experimental results of a turbulent electric field driven by Kelvin-Helmholtz instability associated with laser produced collisionless shock waves. By irradiating an aluminum double plane target with a high-power laser, counterstreaming plasma flows are generated. As the consequence of the two plasma interactions, two shock waves and the contact surface are excited. The shock electric field and transverse modulation of the contact surface are observed by proton radiography. Performing hydrodynamic simulations, we reproduce the time evolutions of the reverse shocks and the transverse modulation driven by Kelvin-Helmholtz instability.
K-shell spectra of solid Al excited by petawatt picosecond laser pulses have been investigated at... more K-shell spectra of solid Al excited by petawatt picosecond laser pulses have been investigated at the Vulcan PW facility. Laser pulses of ultrahigh contrast with an energy of 160 J on the target allow studies of interactions between the laser field and solid state matter at 1e20 W/cm2. Intense X-ray emission of KK hollow atoms (atoms without n = 1 electrons) from thin aluminum foils is observed from optical laser plasma for the first time. Specifically for 1.5 um thin foil targets the hollow atom yield dominates the resonance line emission. It is suggested that the hollow atoms are predominantly excited by the impact of X-ray photons generated by radiation friction to fast electron currents in solid-density plasma due to Thomson scattering and bremsstrahlung in the transverse plasma fields. Numerical simulations of Al hollow atom spectra using the ATOMIC code confirm that the impact of keV photons dominates the atom ionization. Our estimates demonstrate that solid-density plasma generated by relativistic optical laser pulses provide the source of a polychromatic keV range X-ray field of 1e18 W/cm2 intensity, and allows the study of excited matter in the radiation-dominated regime. High-resolution X-ray spectroscopy of hollow atom radiation is found to be a powerful tool to study the properties of high-energy density plasma created by intense X-ray radiation.
Interaction between a central outflow and a surrounding wind is common in astrophysical sources p... more Interaction between a central outflow and a surrounding wind is common in astrophysical sources powered by accretion. Understanding how the interaction might help to collimate the inner central outflow is of interest for assessing astrophysical jet formation paradigms. In this context, we studied the interaction between two nested supersonic plasma flows generated by focusing a long-pulse high-energy laser beam onto a solid target. A nested geometry was created by shaping the energy distribution at the focal spot with a dedicated phase plate. Optical and x-ray diagnostics were used to study the interacting flows. Experimental results and numerical hydrodynamic simulations indeed show the formation of strongly collimated jets. Our work experimentally confirms the “shock-focused inertial confinement” mechanism proposed in previous theoretical astrophysics investigations.
Nuclear Instruments & Methods in Physics Research Section A-accelerators Spectrometers Detectors and Associated Equipment, 2011
We report on the generation of protons with energies of 5.5 MeV when irradiating an H 2 O nano-wi... more We report on the generation of protons with energies of 5.5 MeV when irradiating an H 2 O nano-wire layer grown on a sapphire plate with an intensity of 5 Â 10 17 W/cm 2 . A theoretical model is suggested in which plasma near the tip of the wire is subject to enhanced electrical fields and protons are accelerated to several MeVs.
We have been investigated K-shell radiation of projectile ions and solid media during its interac... more We have been investigated K-shell radiation of projectile ions and solid media during its interaction. The main advantage of the method consists in that the media is transparent for radiation applied for diagnostics, which provides the data acquisition directly from the interaction volume. The projectile and target spectra in the energy range of 1.5^ -^ 8 keV were registered by means of spherically bend crystal spectrometers (FSSR) with a high spatial resolution along the beam propagation. The Ni, Ca and Mg ions accelerated in GSI UNILAC facility to the energies of 11.4 and 5.9 MeV/u were slowed down in solid quartz, quartz aerogels and aluminum media. Low-density (up to 0.02 g/cc) aerogel targets allowed expanding the interaction volume up to 100 times and, accordingly, to resolve the evolution of ion beam velocity and charge states inside the media. Simultaneously, the wavelengths and relative intensities of Ka satellite lines radiated by Si and Al target ions with different charges were measured. This has been provided us to investigate the excited media of the heavy ion track on a timescale of radiation transitions lifetimes (˜20 fs after excitation). Low beam current of 1 uA allowed us to consider the excitation process as a number of statistically independent acts of single heavy ion energy deposition to the media.
K-shell radiation of projectile ions and solid media during its interaction has been investigated... more K-shell radiation of projectile ions and solid media during its interaction has been investigated. The target media are transparent for radiation applied for diagnostics, which provides the data acquisition directly from the interaction volume. The projectile and target spectra in the energy range of 1.5^ -^ 8 keV were registered by spherically bend crystal spectrometers (FSSR) with a high spatial resolution along the beam propagation. The Ni, Ca and Mg ions accelerated in GSI UNILAC facility to the energies of 11.4 MeV/u were slowed down in quartz and aluminum media. Low-density (up to 0.02 g/cc) quartz aerogel targets allowed expanding 100 times the interaction volume and to determine the evolution of ion beam velocity and charge states inside the media. At the same time, the wavelengths and relative intensities of Kalpha satellite lines radiated by Si and Al target ions with different charges were measured. This has been provided us to investigate the excited media of the heavy i...
ABSTRACT K-shell radiation of fast heavy ions penetrating solid matter was used to analyze the st... more ABSTRACT K-shell radiation of fast heavy ions penetrating solid matter was used to analyze the stopping dynamics of ions over more than 80% of the stopping path. The most important advantage of this method is that the data is obtained with a high spatial resolution directly from the interaction volume. In experiments 11.4 MeV/u Ca projectile were slowed down in solid quartz and low-density SiO{sub 2} aerogel targets. Characteristic projectile and target spectra in the photon energy range of 1.5-4 keV were registered by means of spherically bent crystal spectrometers with high spectral and spatial resolution in the direction of the ion beam propagation. K-shell spectra of heavy ions induced by close collisions with target atoms provided information about the projectile charge state and velocity dynamics. The line intensity distribution of the K-shell transitions arising from ions with different ion charges represents the charge state distribution along the ion beam track. The variation of the line Doppler shift due to the ion deceleration in the target material was used to determine the ion velocity dynamics. The spectroscopic analysis of the stopping process was complemented by measurements of the energy loss and ion charge state distribution after the ion beam emerged from the target using a standard time-of-flight method and magnet spectrometer.
2008 Conference on Lasers and Electro-Optics, 2008
ABSTRACT We found that snow nanotubes targets absorb more than 95% of the incident light of a hig... more ABSTRACT We found that snow nanotubes targets absorb more than 95% of the incident light of a high power laser. Fast ions were generated with energies up to 100keV.
A plasma model of relaxation of a medium in heavy ion tracks in condensed matter is proposed. The... more A plasma model of relaxation of a medium in heavy ion tracks in condensed matter is proposed. The model is based on three assumptions: the Maxwell distribution of plasma electrons, localization of plasma inside the track nanochannel and constant values of the plasma electron density and temperature during the X-ray irradiation. It is demonstrated that the plasma relaxation model adequately describes the X-ray spectra observed upon interaction of a fast ion with condensed target. Preassumptions of plasma relaxation model are validated by the molecular dynamics modeling and simulation.
ABSTRACT X-ray production from the interaction of femtosecond laser pulses focused to relativisti... more ABSTRACT X-ray production from the interaction of femtosecond laser pulses focused to relativistic intensity into re-entrant targets etched into silicon has been investigated. K(alpha) and hard x-ray yields were compared when the laser was focused into pyramidal shaped cone targets and wedge shaped targets. Hot electron production is highest in the wedge targets irradiated with transverse polarization, though K(alpha) is maximized with wedge targets and parallel polarization. These results are explained with particle-in-cell simulations. (c) 2008 American Institute of Physics.
Journal of Physics A: Mathematical and General, 2006
ABSTRACT In this paper, we present experimental results on the excitation of solid-state matter b... more ABSTRACT In this paper, we present experimental results on the excitation of solid-state matter by single, energetic heavy ions. The method of x-ray spectroscopy with spatial resolution along the projectile stopping path inside solids was applied to investigate the state of the medium inside the area of heavy-ion tracks. Spectral data of quartz and aluminium media excited by Ni, Ca and Mg ions from the GSI UNILAC accelerator are presented. The ions&#39; initial energies of 11.4 and 5.9 MeV/u and the beam current on the target in the order of 1 µA were chosen. The observation was focused on relative intensities of Kα satellite lines radiated by Si and Al multicharged ions with different charges. The aerogel medium with extremely low bulk density (0.04 g cc−1) was used to investigate the evolution of target media radiation properties during the projectile ions&#39; stopping and, respectively, the change of the ion&#39;s energy deposition into the solids. Due to very short lifetimes of the excited levels for the observed multicharged ions, the data for heavy-ion track area were obtained on tens of femtoseconds time scale after excitation. For further analysis and obtaining quantitative description of heavy-ion track parameters, the methods of numerical simulation are suggested.
X-ray emission and possibility of obtaining radiography images with laser plasma X-ray source ope... more X-ray emission and possibility of obtaining radiography images with laser plasma X-ray source operating at atmospheric pressure and room temperature is investigated. Table top 40 fs 100 uJ laser and Cu and Fe bulk metal targets were used to produce X-ray emission in spectral range of 3-10 keV. The spectra, yield and size of X-ray source were measured under different experimental conditions. X-ray photons of up to 10 keV energy are produced effectively even by relatively low laser intensity < 1015 W/cm2. The source is applied for absorption imaging provided the sensitivity on 10 mum sample thickness and 30 mum spatial resolution of microstructures. The ability to perform phase contrast measurements is demonstrated. The advantages of the proposed method are in smart setup of investigated object within air environment; spectral range tunability; and sensitivity to low-contrast or micron thin details.
A novel type of submicron ion radiography designed to image low-contrast objects, including nanof... more A novel type of submicron ion radiography designed to image low-contrast objects, including nanofoils, membranes and biological structures, is proposed. It is based on femtosecond-laser-driven-cluster-plasma source of multicharged ions and polymer dosimeter film CR-39. The intense isotropic ion flow was produced by femtosecond Ti:Sa laser pulses with intensity ∼ 4x10 17 W/cm 2 absorbed in the supersonic jet of the mixed He and CO2 gases. Two Focusing Spectrometers with Spatial Resolution (FSSR) were used to measure X-ray spectra of H-and He-like multicharged oxygen ions. The spectra testify that ions with energy more than 300 keV were radiated in different directions from the plasma source. High contrast ion radiography images were obtained for 2000 dpi metal mesh, 1 μm polypropylene and 100 nm Zr foils as well as for the different biological objects. Images were recorded on a 1 mm thick CR-39 detector, placed in contact with back surface of the imaged samples at the distances 140 -160 mm from the ion source. The spatial resolution of the image no worse than 600 nm was provided. A difference in object thickness of 100 nm was very well resolved for both Zr and polymer foils. The ion radiography images recorded at different angles from the source, demonstrated almost uniform spatial distribution of ion with total number of 10 8 per shot.
A plasma model for relaxation of a medium in heavy ion tracks in condensed matter is proposed. Th... more A plasma model for relaxation of a medium in heavy ion tracks in condensed matter is proposed. The model is based on three assumptions: the Maxwell distribution of plasma electrons, localization of plasma inside the track nanochannel, and constant values of the plasma electron density and temperature during the X-ray irradiation. It is demonstrated that the plasma relaxation model adequately describes the X-ray spectra observed upon interaction of a fast ion with condensed target. Preassumptions of plasma relaxation model are validated by the molecular dynamics modeling and simulation.
ABSTRACT Hard x rays are generated in laminar helium flow in atmosphere (without a vacuum vessel)... more ABSTRACT Hard x rays are generated in laminar helium flow in atmosphere (without a vacuum vessel) through the interaction of tightly focused 35 fs laser pulses of varying energy with a Cu target. The energy conversion efficiency from laser to K alpha x rays is measured to be 5.4x10(-6), giving a flux of 5.9x10(9) photons/s into 2 pi sr from a source measuring approximately 9x12 mu m(2) in size (verticalxhorizontal). Results are compared to those measured in vacuum and in static helium environments. (c) 2008 American Institute of Physics.
The short review on the possible applications of the hollow ion spectra for the diagnostics of th... more The short review on the possible applications of the hollow ion spectra for the diagnostics of the high-temperature plasma created by intensive laser and particle beams is presented. Because of the hollow ion spectra features are defined mainly by the mechanisms of their excitation, we consider the various types of the high-temperature plasma where different excitation processes are important. It is shown that like ordinary spectral lines, spectra of the hollow ions offer considerable diagnostic opportunities. At the present time, hollow ion spectra are used mainly to investigate plasma heated by X-ray radiation, but the hollow ions must be generated when plasma is heated by fast heavy ion beams too. In this case, the resultant substance state will be also characterized by solid-state density, and some spatial regions of targets will have relatively low temperatures, i.e., will be a nonideal plasma. It is emphasized that hollow ion spectra are promising diagnostic tool for both nonideal plasma and warm dense matter.
Although bipolar jets are seen emerging from a wide variety of astrophysical systems, the issue o... more Although bipolar jets are seen emerging from a wide variety of astrophysical systems, the issue of their formation and morphology beyond their launching is still under study. Our scaled laboratory experiments, representative of young stellar object outflows, reveal that stable and narrow collimation of the entire flow can result from the presence of a poloidal magnetic field whose strength is consistent with observations.The laboratory plasma becomes focused with an interior cavity.This gives rise to a standing conical shock from which the jet emerges. Following simulations of the process at the full astrophysical scale,we conclude that it can also explain recently discovered x-ray emission features observed in low-density regions at the base of protostellar jets, such as the well-studied jet HH 154.
We report the experimental results of a turbulent electric field driven by Kelvin-Helmholtz insta... more We report the experimental results of a turbulent electric field driven by Kelvin-Helmholtz instability associated with laser produced collisionless shock waves. By irradiating an aluminum double plane target with a high-power laser, counterstreaming plasma flows are generated. As the consequence of the two plasma interactions, two shock waves and the contact surface are excited. The shock electric field and transverse modulation of the contact surface are observed by proton radiography. Performing hydrodynamic simulations, we reproduce the time evolutions of the reverse shocks and the transverse modulation driven by Kelvin-Helmholtz instability.
K-shell spectra of solid Al excited by petawatt picosecond laser pulses have been investigated at... more K-shell spectra of solid Al excited by petawatt picosecond laser pulses have been investigated at the Vulcan PW facility. Laser pulses of ultrahigh contrast with an energy of 160 J on the target allow studies of interactions between the laser field and solid state matter at 1e20 W/cm2. Intense X-ray emission of KK hollow atoms (atoms without n = 1 electrons) from thin aluminum foils is observed from optical laser plasma for the first time. Specifically for 1.5 um thin foil targets the hollow atom yield dominates the resonance line emission. It is suggested that the hollow atoms are predominantly excited by the impact of X-ray photons generated by radiation friction to fast electron currents in solid-density plasma due to Thomson scattering and bremsstrahlung in the transverse plasma fields. Numerical simulations of Al hollow atom spectra using the ATOMIC code confirm that the impact of keV photons dominates the atom ionization. Our estimates demonstrate that solid-density plasma generated by relativistic optical laser pulses provide the source of a polychromatic keV range X-ray field of 1e18 W/cm2 intensity, and allows the study of excited matter in the radiation-dominated regime. High-resolution X-ray spectroscopy of hollow atom radiation is found to be a powerful tool to study the properties of high-energy density plasma created by intense X-ray radiation.
Interaction between a central outflow and a surrounding wind is common in astrophysical sources p... more Interaction between a central outflow and a surrounding wind is common in astrophysical sources powered by accretion. Understanding how the interaction might help to collimate the inner central outflow is of interest for assessing astrophysical jet formation paradigms. In this context, we studied the interaction between two nested supersonic plasma flows generated by focusing a long-pulse high-energy laser beam onto a solid target. A nested geometry was created by shaping the energy distribution at the focal spot with a dedicated phase plate. Optical and x-ray diagnostics were used to study the interacting flows. Experimental results and numerical hydrodynamic simulations indeed show the formation of strongly collimated jets. Our work experimentally confirms the “shock-focused inertial confinement” mechanism proposed in previous theoretical astrophysics investigations.
Nuclear Instruments & Methods in Physics Research Section A-accelerators Spectrometers Detectors and Associated Equipment, 2011
We report on the generation of protons with energies of 5.5 MeV when irradiating an H 2 O nano-wi... more We report on the generation of protons with energies of 5.5 MeV when irradiating an H 2 O nano-wire layer grown on a sapphire plate with an intensity of 5 Â 10 17 W/cm 2 . A theoretical model is suggested in which plasma near the tip of the wire is subject to enhanced electrical fields and protons are accelerated to several MeVs.
We have been investigated K-shell radiation of projectile ions and solid media during its interac... more We have been investigated K-shell radiation of projectile ions and solid media during its interaction. The main advantage of the method consists in that the media is transparent for radiation applied for diagnostics, which provides the data acquisition directly from the interaction volume. The projectile and target spectra in the energy range of 1.5^ -^ 8 keV were registered by means of spherically bend crystal spectrometers (FSSR) with a high spatial resolution along the beam propagation. The Ni, Ca and Mg ions accelerated in GSI UNILAC facility to the energies of 11.4 and 5.9 MeV/u were slowed down in solid quartz, quartz aerogels and aluminum media. Low-density (up to 0.02 g/cc) aerogel targets allowed expanding the interaction volume up to 100 times and, accordingly, to resolve the evolution of ion beam velocity and charge states inside the media. Simultaneously, the wavelengths and relative intensities of Ka satellite lines radiated by Si and Al target ions with different charges were measured. This has been provided us to investigate the excited media of the heavy ion track on a timescale of radiation transitions lifetimes (˜20 fs after excitation). Low beam current of 1 uA allowed us to consider the excitation process as a number of statistically independent acts of single heavy ion energy deposition to the media.
Uploads
Papers by Sergey Pikuz
created by intensive laser and particle beams is presented. Because of the hollow ion spectra features are defined mainly by
the mechanisms of their excitation, we consider the various types of the high-temperature plasma where different excitation processes are important. It is shown that like ordinary spectral lines, spectra of the hollow ions offer considerable diagnostic
opportunities. At the present time, hollow ion spectra are used mainly to investigate plasma heated by X-ray radiation, but
the hollow ions must be generated when plasma is heated by fast heavy ion beams too. In this case, the resultant substance
state will be also characterized by solid-state density, and some spatial regions of targets will have relatively low temperatures, i.e., will be a nonideal plasma. It is emphasized that hollow ion spectra are promising diagnostic tool for both nonideal plasma and warm dense matter.
plasma interactions, two shock waves and the contact surface are excited. The shock electric field and transverse modulation of the contact surface are observed by proton radiography. Performing hydrodynamic simulations, we reproduce the time evolutions of the reverse shocks and the transverse modulation driven by Kelvin-Helmholtz instability.
of interactions between the laser field and solid state matter at 1e20 W/cm2. Intense X-ray emission of KK hollow atoms (atoms without n = 1 electrons) from thin aluminum foils is observed from optical laser
plasma for the first time. Specifically for 1.5 um thin foil targets the hollow atom yield dominates the resonance line emission. It is suggested that the hollow atoms are predominantly excited by the impact of X-ray photons generated by radiation friction to fast electron currents in solid-density plasma due to Thomson scattering and bremsstrahlung in the transverse plasma fields. Numerical simulations of Al hollow atom spectra using the ATOMIC code confirm that the impact of keV photons dominates the atom ionization. Our estimates demonstrate that solid-density plasma generated by relativistic optical laser pulses provide the source of a polychromatic keV range X-ray field of 1e18 W/cm2 intensity, and allows the study of excited matter in the radiation-dominated regime. High-resolution X-ray spectroscopy of hollow atom radiation is found to be a powerful tool to study the properties of high-energy density plasma created by intense X-ray radiation.
between two nested supersonic plasma flows generated by focusing a long-pulse high-energy laser beam onto a solid target. A nested geometry was created by shaping the energy distribution at the focal spot with a dedicated phase plate. Optical and x-ray diagnostics were used to study the interacting flows.
Experimental results and numerical hydrodynamic simulations indeed show the formation of strongly collimated jets. Our work experimentally confirms the “shock-focused inertial confinement” mechanism proposed in previous theoretical astrophysics investigations.
created by intensive laser and particle beams is presented. Because of the hollow ion spectra features are defined mainly by
the mechanisms of their excitation, we consider the various types of the high-temperature plasma where different excitation processes are important. It is shown that like ordinary spectral lines, spectra of the hollow ions offer considerable diagnostic
opportunities. At the present time, hollow ion spectra are used mainly to investigate plasma heated by X-ray radiation, but
the hollow ions must be generated when plasma is heated by fast heavy ion beams too. In this case, the resultant substance
state will be also characterized by solid-state density, and some spatial regions of targets will have relatively low temperatures, i.e., will be a nonideal plasma. It is emphasized that hollow ion spectra are promising diagnostic tool for both nonideal plasma and warm dense matter.
plasma interactions, two shock waves and the contact surface are excited. The shock electric field and transverse modulation of the contact surface are observed by proton radiography. Performing hydrodynamic simulations, we reproduce the time evolutions of the reverse shocks and the transverse modulation driven by Kelvin-Helmholtz instability.
of interactions between the laser field and solid state matter at 1e20 W/cm2. Intense X-ray emission of KK hollow atoms (atoms without n = 1 electrons) from thin aluminum foils is observed from optical laser
plasma for the first time. Specifically for 1.5 um thin foil targets the hollow atom yield dominates the resonance line emission. It is suggested that the hollow atoms are predominantly excited by the impact of X-ray photons generated by radiation friction to fast electron currents in solid-density plasma due to Thomson scattering and bremsstrahlung in the transverse plasma fields. Numerical simulations of Al hollow atom spectra using the ATOMIC code confirm that the impact of keV photons dominates the atom ionization. Our estimates demonstrate that solid-density plasma generated by relativistic optical laser pulses provide the source of a polychromatic keV range X-ray field of 1e18 W/cm2 intensity, and allows the study of excited matter in the radiation-dominated regime. High-resolution X-ray spectroscopy of hollow atom radiation is found to be a powerful tool to study the properties of high-energy density plasma created by intense X-ray radiation.
between two nested supersonic plasma flows generated by focusing a long-pulse high-energy laser beam onto a solid target. A nested geometry was created by shaping the energy distribution at the focal spot with a dedicated phase plate. Optical and x-ray diagnostics were used to study the interacting flows.
Experimental results and numerical hydrodynamic simulations indeed show the formation of strongly collimated jets. Our work experimentally confirms the “shock-focused inertial confinement” mechanism proposed in previous theoretical astrophysics investigations.