Hostname: page-component-76fb5796d-22dnz Total loading time: 0 Render date: 2024-04-27T02:19:00.824Z Has data issue: false hasContentIssue false

Self focusing of a laser pulse in plasma with periodic density ripple

Published online by Cambridge University Press:  19 March 2009

Sukhdeep Kaur*
Affiliation:
Center for Energy Studies, Indian Institute of Technology Delhi, New Delhi, India
A.K. Sharma
Affiliation:
Center for Energy Studies, Indian Institute of Technology Delhi, New Delhi, India
*
Address correspondence and reprint requests to: S. Kaur, Center for Energy Studies, Indian Institute of Technology Delhi, New Delhi-110016, India. E-mail: sukhdeep.iitd@gmail.com

Abstract

Propagation of an intense laser pulse in plasma with a periodically modulated density is considered using envelope equations. The laser induces modifications of the plasma refractive index via relativistic and ponderomotive nonlinearities. In the region of high plasma density, the self focusing effect of nonlinearity suppresses the diffraction divergence, and the laser converges. As the beam enters into the low density region, the diffraction tends to diverge it offsetting the convergence due to the curvature it has acquired. For a given set of plasma parameters, there is a critical power of the laser above which it propagates in a periodically focused manner. Below this power the laser undergoes overall divergence. At substantially higher powers, the laser beam continues to converge until the saturation effect of nonlinearity suppresses the self focusing and diffraction predominates. The effect of density ripple is to cause overall increase in the self focusing length. The minimum spot size decreases with the wave number of the ripple.

Type
Research Article
Copyright
Copyright © Cambridge University Press 2009

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

REFERENCES

Brandi, H.S., Manus, C. & Mainfray, G. (1993). Relativistic self-focusing of ultraintense laser pulses in inhomogeneous underdense plasma. Phys. Rev. E 47, 3780.CrossRefGoogle Scholar
Bulano, V.S.V., Esirkepov, T.Zh., Naumova, N.M. & Sokolov, I.V. (2003). High-order harmonics from an ultraintense laser pulse propagating inside a fibre. Phys. Rev. E 67, 0164051–5.Google Scholar
Chessa, P., Mora, P. & Anstonsen Thomas, M. Jr. (1998). Numerical simulation of short laser pulse relativistic self-focusing in underdense plasma. Phys. Plasmas 5, 34513458.CrossRefGoogle Scholar
Faenov, A.Ya., Magunov, A.I., Pikuz, T.A., Skobelev, I.Y., Gasilov, S.V., Stagira, S., Calegari, F., Nisoli, M., Silvestri, S.De., Poletto, L., Villoresi, P. & Andreev, A.A. (2007). X-ray spectroscopy observation of fast ions generation in plasma produced by short low- contrast laser pulse irradiation of solid. Laser Part. Beams 25, 267275.CrossRefGoogle Scholar
Faure, J., Malka, V., Marques, J.R., David, P.G., Amiranoff, F., Phuoc, K.T. & Rousse, A. (2002). Effects of pulse duration on self-focusing of ultra-short lasers in underdense plasmas. Phys. Plasmas 9, 756759.CrossRefGoogle Scholar
Feit, M.D., Komashko, A.M., Rubenchik, A.M. & Turitsyn, S.K. (1998). Electron cavitation and relativistic self-focusing in underdense plasma. Phys. Rev. E 57, 71227125.CrossRefGoogle Scholar
Ghoranneviss, M., Malekynia, B., Hora, H., Miley, G.H. & He, X. (2008). Inhibition factor reduces fast ignition threshold for laser fusion using nonlinear force driven block acceleration. Laser Part. Beams 26, 105111.CrossRefGoogle Scholar
Gill, T.S. & Saini, N.S. (2007). Nonlinear interaction of a ripped laser beam with an electrostatic upper hybrid wave in collisional plasma. laser Part. Beams 25, 283293.CrossRefGoogle Scholar
Gupta, D., Hur, M., Hwang, I., Suk, H. & Sharma, A.K. (2007). Plasma density ramp for relativistic self-focusing of an intense pulse. Opt. Soc. Ame. B 24, 11551159.CrossRefGoogle Scholar
Hafeez, S., Shaikh, N.M. & Baig, M.A. (2008). Spectroscopic studies of Ca plasma generated by the fundamental, second, and third harmonics of a Nd: YAG laser. Laser Part. Beams 26, 4150.CrossRefGoogle Scholar
Hafizi, B., Ting, A., Sprangle, P. & Hubbard, R.F. (2000). Relativistic focusing and ponderomotive channeling of intense laser beams. Phys. Rev. E 62, 41204125.CrossRefGoogle ScholarPubMed
Hora, H. (2007). New aspects for fusion energy using inertial confinement. Laser Part. Beams 25, 3745.CrossRefGoogle Scholar
Kuo, C.C., Pai, C.H., Lin, M.W., Lee, K.H., Lin, J.Y., Wang, J. & Chen, S.Y. (2007). Enhancement of relativistic harmonic generation by an optically-preformed periodic plasma waveguide. Phys. Rev. Lett. 98, 033901–6.CrossRefGoogle ScholarPubMed
Laska, L., Badziak, J., Boody, F.P., Gammino, S., Jungwirth, K., Krasa, J., Krousky, E., Parys, P., Pfeifer, M., Rohlena, K., Ryc, L., Skala, J., Torrisi, L., Ullschmied, J. & Wolowski, J. (2007 a). Factors influencing parameters of laser ion Sources. Laser Part. Beams 25, 199205.CrossRefGoogle Scholar
Laska, L., Badziak, J., Gammino, S., Jungwirth, K., Kasperczuk, A., Krasa, J., Krousky, E., Kubes, P., Parys, P., Pfeifer, M., Pisarczyk, T., Rohlena, K., Rosinski, M., Ryc, L., Skala, J., Torrisi, U.J., Velyhan, A. & Wolowski, J. (2007 b). The influence of an intense laser beam interaction with preformed plasma on the characteristics of emitted ion strems. Laser Part. Beams 25, 549556.CrossRefGoogle Scholar
Lin, M.W., Chen, Y.M., Pai, C.H., Kuo, C.C., Lee, K.H., Wang, J. & Chen, S.Y. (2006). Programmable fabrication of spatial structures in a gas jet by laser machining with a spatial light modulator. Phys. Plasmas 13, 1107011–4.CrossRefGoogle Scholar
Liu, C.S. & Tripathi, V.K. (1994). Interaction of Electromagnetic Waves and Electron Beams with Plasmas. Singapore: World Scientific.CrossRefGoogle Scholar
Parashar, J. & Pandey, H.D. (1992). Second-harmonic generation of laser radiation in a plasma with a density ripple. IEEE Trans. Plasma Sci. 20, 996999.CrossRefGoogle Scholar
Purohit, G., Chauhan, P.K. & Sharma, R.P. (2008). Excitation of an upper hybrid wave by a high power laser beam in plasma. Laser Part. Beams 26, 6167.CrossRefGoogle Scholar
Ren, C., Duda, R.G., Hemker, R.G., Mori, W.B., Katsouleas, T., Anstonsen, T.M. Jr. & Mora, P. (2001). Compressing and focusing a short laser pulse by a thin plasma lens. Phys. Rev. E 63, 026411.CrossRefGoogle Scholar
Sodha, M.S., Ghatak, A.K. & Tripathi, V.K. (1974). Self- focusing of Laser Beams in Dielectric, Plasmas and Semiconductors. New Delhi: Tata McGraw-Hill.Google Scholar
Torrisi, L., Margarone, D., Laska, L., Krasa, A., Velyhan, A., Pfeifer, M., Ullschmied, J. & Rycl, L. (2008). Self- focusing effect in Au-target induced by high power pulsed laser at PALS. Laser Part. Beams 26, 379387.CrossRefGoogle Scholar
Tripathi, V.K., Taguchi, T. & Liu, C.S. (2005). Plasma channel charging by an intense short pulse laser and ion coulomb explosion. Phys. Plasmas 12, 043106.CrossRefGoogle Scholar
Upadhyay, A., Tripath, I.V.K., Sharma, A.K. & Pant, H.C. (2002). Asymmetric self focusing of a laser pulse in plasma. J. Plasma Phys. 68, 7580.CrossRefGoogle Scholar