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22 results on '"Culfa, O."'

3. Micron-Scale Mapping of Megagauss Magnetic Fields in Petawatt Laser-Solid Interactions

Author

Chatterjee, Gourab, Singh, Prashant Kumar, Robinson, A. P. L., Booth, N., Culfa, O., Dance, R. J., Gizzi, L. A., Gray, R. J., Green, J. S., Koester, P., Kumar, G. Ravindra, Labate, L., Lad, Amit D., Lancaster, K. L., Pasley, J., Woolsey, N. C., and Rajeev, P. P.

Subjects
Physics - Plasma Physics
Abstract

We report spatially and temporally resolved measurements of magnetic fields generated by petawatt laser-solid interactions with high spatial resolution, using optical polarimetry. The polarimetric measurements map the megagauss magnetic field profiles generated by the fast electron currents at the target rear. The magnetic fields at the rear of a 50 $\mu$m thick aluminum target exhibit distinct and unambiguous signatures of electron beam filamentation. These results are corroborated by hybrid simulations., Comment: 5 pages, 5 figures

Published
2013

4. Measurements of hot electron spectra from high irradiance laser plasmas

Author

Culfa, O. and Tallents, G. J.

Subjects
530
Abstract

This thesis presents measurements of the production of hot electrons during laser interactions in the irradiance range 10^{16} -10^{20} W cm^{−2} . This intensity regime is accessible with modest ultra-short lasers at ∼ 10^{16} Wcm^{−2} where resonance absorption dominates the electron acceleration. At the higher irradiances (10^{18} -10^{20} W cm^{−2}), petawatt class lasers are required where J × B electron accelera- tion occurs. Fast electron generation using the VULCAN Petawatt laser (irradiances ∼ 10^{20} W cm^{−2}) and the LASERIX facility (irradiances ∼ 10^{16} W cm^{−2}) have been investigated. Using the Vulcan Petawatt laser, with pulse duration of 1 - 2 ps at intensities greater than 10^{20} W cm^{−2}, electron energies up to 120 MeV with temperatures 20 - 30 MeV have been observed. A pre pulse was used to create an expanding plasma in which the high irradiance pulse was incident and the scale length of the pre pulse produced plasma was measured using optical probing. It was found that the number of hot electrons produced at 10^{20} W cm^{−2} linearly increases with the measured pre pulse plasma scale length indicating that the electron acceleration is dependent on the pre-pulse plasma volume. 2D PIC simulations are in agreement with experimentally measured temperatures, while 1D PIC simulations only agree for shorter scale length plasmas (L≤ 7.5 μm). Plasma channels are formed with longer scale length plasmas, but these channels do not result in greater acceleration of electrons as they are not sufficiently nar- row. The role of hot electrons in heating solid targets is experimentally examined and it is found that radiation effects on target heating when a pre pulse is present dominate over hot electron heating.

Published
2014

5. Exotic dense matter states pumped by relativistic laser plasma in the radiation dominant regime

Author

Colgan, J., Abdallah, Jr., J., Faenov, A. Ya., Pikuz, S. A., Wagenaars, E., Booth, N., Brown, C. R. D., Culfa, O., Dance, R. J., Evans, R. G., Gray, R. J., Hoarty, D. J., Kaempfer, T., Lancaster, K. L., McKenna, P., Rossall, A. L., Skobelev, I. Yu., Schulze, K. S., Uschmann, I., Zhidkov, A. G., and Woolsey, N. C.

Subjects
Physics - Plasma Physics, Physics - Atomic Physics
Abstract

The properties of high energy density plasma are under increasing scrutiny in recent years due to their importance to our understanding of stellar interiors, the cores of giant planets$^{1}$, and the properties of hot plasma in inertial confinement fusion devices$^2$. When matter is heated by X-rays, electrons in the inner shells are ionized before the valence electrons. Ionization from the inside out creates atoms or ions with empty internal electron shells, which are known as hollow atoms (or ions)$^{3,4,5}$. Recent advances in free-electron laser (FEL) technology$^{6,7,8,9}$ have made possible the creation of condensed matter consisting predominantly of hollow atoms. In this Letter, we demonstrate that such exotic states of matter, which are very far from equilibrium, can also be formed by more conventional optical laser technology when the laser intensity approaches the radiation dominant regime$^{10}$. Such photon-dominated systems are relevant to studies of photoionized plasmas found in active galactic nuclei and X-ray binaries$^{11}$. Our results promote laser-produced plasma as a unique ultra-bright x-ray source for future studies of matter in extreme conditions as well as for radiography of biological systems and for material science studies$^{12,13,14,15}$.

Published
2012
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6. Diagnosis of Radiation Heating in Iron Buried Layer Targets

Author

Shahzad, M., Tallents, G. J., Culfa, O., Rossall, A. K., Wilson, L. A., Rose, S. J., Guilbaud, O., Kazamias, S., Pittman, M., Cassou, K., Demailly, J., Delmas, O., Mestrallain, A., Farjardo, M., Ros, D., Rocca, Jorge, editor, Menoni, Carmen, editor, and Marconi, Mario, editor

Published
2016
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8. Diagnosis of Radiation Heating in Iron Buried Layer Targets

Author

Shahzad, M., primary, Tallents, G. J., additional, Culfa, O., additional, Rossall, A. K., additional, Wilson, L. A., additional, Rose, S. J., additional, Guilbaud, O., additional, Kazamias, S., additional, Pittman, M., additional, Cassou, K., additional, Demailly, J., additional, Delmas, O., additional, Mestrallain, A., additional, Farjardo, M., additional, and Ros, D., additional

Published
2015
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11. Micron-scale mapping of megagauss magnetic fields using optical polarimetry to probe hot electron transport in petawatt-class laser-solid interactions

Author

Chatterjee, Gourab, primary, Singh, Prashant Kumar, additional, Robinson, A. P. L., additional, Blackman, D., additional, Booth, N., additional, Culfa, O., additional, Dance, R. J., additional, Gizzi, L. A., additional, Gray, R. J., additional, Green, J. S., additional, Koester, P., additional, Kumar, G. Ravindra, additional, Labate, L., additional, Lad, Amit D., additional, Lancaster, K. L., additional, Pasley, J., additional, Woolsey, N. C., additional, and Rajeev, P. P., additional

Published
2017
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13. Plasma scale-length effects on electron energy spectra in high-irradiance laser plasmas

Author

Culfa, O., primary, Tallents, G. J., additional, Rossall, A. K., additional, Wagenaars, E., additional, Ridgers, C. P., additional, Murphy, C. D., additional, Dance, R. J., additional, Gray, R. J., additional, McKenna, P., additional, Brown, C. D. R., additional, James, S. F., additional, Hoarty, D. J., additional, Booth, N., additional, Robinson, A. P. L., additional, Lancaster, K. L., additional, Pikuz, S. A., additional, Faenov, A. Ya., additional, Kampfer, T., additional, Schulze, K. S., additional, Uschmann, I., additional, and Woolsey, N. C., additional

Published
2016
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14. Exotic dense-matter states pumped by a relativistic laser plasma in the radiation-dominated regime

Author

Colgan, J., Abdallah, Jr., J., Faenov, A. Ya., Pikuz, S. A., Wagenaars, E., Booth, N., Brown, C. R. D., Culfa, O., Dance, R. J., Evans, R. G., Gray, R. J., Hoarty, D. J., Kaempfer, T., Lancaster, K. L., McKenna, P., Rossall, A. L., Skobelev, I. Yu., Schulze, K. S., Uschmann, I., Zhidkov, A. G., and Woolsey, N. C.

Subjects
Physics, Atomic Physics (physics.atom-ph), Thomson scattering, Bremsstrahlung, FOS: Physical sciences, General Physics and Astronomy, Plasma, Electron, Laser, 01 natural sciences, Physics - Plasma Physics, Spectral line, Physics - Atomic Physics, 010305 fluids & plasmas, law.invention, Plasma Physics (physics.plasm-ph), law, 0103 physical sciences, Atom, State of matter, Atomic physics, 010306 general physics, QC
Abstract

The properties of high energy density plasma are under increasing scrutiny in recent years due to their importance to our understanding of stellar interiors, the cores of giant planets$^{1}$, and the properties of hot plasma in inertial confinement fusion devices$^2$. When matter is heated by X-rays, electrons in the inner shells are ionized before the valence electrons. Ionization from the inside out creates atoms or ions with empty internal electron shells, which are known as hollow atoms (or ions)$^{3,4,5}$. Recent advances in free-electron laser (FEL) technology$^{6,7,8,9}$ have made possible the creation of condensed matter consisting predominantly of hollow atoms. In this Letter, we demonstrate that such exotic states of matter, which are very far from equilibrium, can also be formed by more conventional optical laser technology when the laser intensity approaches the radiation dominant regime$^{10}$. Such photon-dominated systems are relevant to studies of photoionized plasmas found in active galactic nuclei and X-ray binaries$^{11}$. Our results promote laser-produced plasma as a unique ultra-bright x-ray source for future studies of matter in extreme conditions as well as for radiography of biological systems and for material science studies$^{12,13,14,15}$.

Published
2012

16. Plasma scale length effects on protons generated in ultra-intense laser–plasmas.

Author

Culfa, O., Tallents, G.J., Korkmaz, M.E., Rossall, A.K., Wagenaars, E., Ridgers, C.P., Murphy, C.D., Booth, N., Carroll, D.C., Wilson, L.A., Lancaster, K.L., and Woolsey, N.C.

Abstract

The energy spectra of protons generated by ultra-intense (1020 W cm−2) laser interactions with a preformed plasma of scale length measured by shadowgraphy are presented. The effects of the preformed plasma on the proton beam temperature and the number of protons are evaluated. Two-dimensional EPOCH particle-in-cell code simulations of the proton spectra are found to be in agreement with measurements over a range of experimental parameters. [ABSTRACT FROM PUBLISHER]

Published
2017
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17. Hot electron production in laser solid interactions with a controlled pre-pulse

Author

Culfa, O., primary, Tallents, G. J., additional, Wagenaars, E., additional, Ridgers, C. P., additional, Dance, R. J., additional, Rossall, A. K., additional, Gray, R. J., additional, McKenna, P., additional, Brown, C. D. R., additional, James, S. F., additional, Hoarty, D. J., additional, Booth, N., additional, Robinson, A. P. L., additional, Lancaster, K. L., additional, Pikuz, S. A., additional, Faenov, A. Ya., additional, Kampfer, T., additional, Schulze, K. S., additional, Uschmann, I., additional, and Woolsey, N. C., additional

Published
2014
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18. Detailed analysis of hollow ions spectra from dense matter pumped by X-ray emission of relativistic laser plasma

Author

Hansen, S. B., primary, Colgan, J., additional, Faenov, A. Ya., additional, Abdallah, J., additional, Pikuz, S. A., additional, Skobelev, I. Yu., additional, Wagenaars, E., additional, Booth, N., additional, Culfa, O., additional, Dance, R. J., additional, Tallents, G. J., additional, Evans, R. G., additional, Gray, R. J., additional, Kaempfer, T., additional, Lancaster, K. L., additional, McKenna, P., additional, Rossall, A. K., additional, Schulze, K. S., additional, Uschmann, I., additional, Zhidkov, A. G., additional, and Woolsey, N. C., additional

Published
2014
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19. Probing of laser-irradiated solid targets using extreme ultraviolet radiation

Author

Tallents, G. J., primary, Shahzad, M., additional, Rossall, A. K., additional, Guilbaud, O., additional, Kazamias, S., additional, Pittman, M., additional, Cassou, K., additional, Demailly, J., additional, Delmas, O., additional, Mestrallain, A., additional, Aslanyan, V., additional, Culfa, O., additional, Wilson, L. A., additional, Farjardo, M., additional, and Ros, D., additional

Published
2013
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20. Exotic Dense-Matter States Pumped by a Relativistic Laser Plasma in the Radiation-Dominated Regime

Author

Colgan, J., primary, Abdallah, J., additional, Faenov, A. Ya., additional, Pikuz, S. A., additional, Wagenaars, E., additional, Booth, N., additional, Culfa, O., additional, Dance, R. J., additional, Evans, R. G., additional, Gray, R. J., additional, Kaempfer, T., additional, Lancaster, K. L., additional, McKenna, P., additional, Rossall, A. L., additional, Skobelev, I. Yu., additional, Schulze, K. S., additional, Uschmann, I., additional, Zhidkov, A. G., additional, and Woolsey, N. C., additional

Published
2013
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