Effect of axial magnetic field tapering on whistler-pumped FEL amplifier in collective Raman regime operation

  • Authors

    • Ram Gopal INDIAN INSTITUTE OF TECHNOLOGY (BHU), VARANASI, INDIA
    • Pradip Kumar Jain
    • Pradip Kumar Jain
    2018-09-05
    https://doi.org/10.14419/ijet.v7i4.15298
  • FEL Amplifier, Linear Tapered Axial Magnetic Field, Magnetic Wiggler and Whistler.

  • The dispersion relation of the FEL Amplifiers is sensitive to the linear tapered strong axial magnetic fields, electron cyclotron frequency and plasma frequency of electrons. For the synchronism of the pumped frequency, it should be closed to electron cyclotron frequency which is resonantly enhanced the wiggler wave number that produces the amplifier radiation for higher frequency from sub millimeter wave to optical ranges. The guiding of radiation signal into the waveguide and charge neutralization phenomenon, the beam density should be greater than the background plasma density with tapered strong axial magnetic field. It is quite considerable that radiation signal slowed down at much higher background plasma density comparable to the density of beams and enhanced the instability growth rate also. In Raman Regime operation, the growth rate decreases as increases with operation frequency of the amplifier, however, the growth rate is larger in this regime. It is noted that as increases with background plasma density, the beat wave frequency of the Ponderomotive waves is increases thus the mechanism of background plasma density can serve for tenability of the higher frequencies. The tapering of the strong guided magnetic field is a crucial role for enhancing the efficiency of the net transfer energy as well as reduction of interaction region along the axis. It is observed that, an efficiency of the transfer energy enhanced by while the reduction along the interaction region of about with the variation of tapering in a strong axial guided magnetic fields.

     

     

  • References

    1. [1] Pant KK & Tripathi VK, “Free Electron Laser Operation in the Whistler Modeâ€, IEEE Transactions on plasma science, Vol. 22, No. 3, (1994). https://doi.org/10.1109/27.297869.

      [2] Sharma A & Tripathi VK, “A plasma filled gyrotron pumped free electron laserâ€, Phys. Plasmas, Vol. 3, (1996), pp. 3116. https://doi.org/10.1063/1.871658.

      [3] Gopal R & Jain PK, “Tapering effect of an axial magnetic field on whistler-pumped FEL Amplifierâ€, IRACTS-Engineering Science and Technology: An International journal (ESTIJ), Vol. 8, No. 2, (2018).

      [4] Marshall TC, Free Electron Lasers, MacMillan, New York, (1985).

      [5] Liu CS & Tripathi VK, Interaction of electromagnetic waves with electron beams and plasmas, World Scientific, (1994). https://doi.org/10.1142/2189.

      [6] Botao Jia, “Study of Storage Ring Free Laser using experimental and simulation approachesâ€, Ph.D. Dissertation, Department of Physics, Duke University, China, (2011).

      [7] Pae KH & Hahn SJ, “Compact sized IR source using electromagnetic-wave wigglersâ€, Journal of the Korean Physical Society, Vol. 40, No. 5, (2002), pp. 832-836.

      [8] Patrick Shea GO & Freund HP, “Free Electron Lasers: Status and Applicationsâ€, Vol. 292, Issue-5523, (2001), p. 1853-1858.

      [9] Sharma A & Tripathi VK, “A whistler pumped free electron laserâ€, Phys. Fluids, Vol. 3I, (1988), pp. 3375-3378. https://doi.org/10.1063/1.866902.

      [10] Sharma A & Tripathi VK, “Kinetic theory of a whistler-pumped free electron laser,†Phys. of Fluids, Vol. B 5, No.1, (1993).

      [11] Jong RA, Scharlemann ET & Fawley WM, “Wiggler taper optimization for free electron laser amplifier (FELA) with moderate space-charge effectsâ€, Nuclear Instruments and Methods in Physics Research, Vol. A 272, (1988), p. 99-105.

      [12] Pant KK & Tripathi VK, “Nonlocal theory of a whistler pumped free electron laserâ€, Physics of Plasmas, Vol. 1, (1994), pp. 1025. https://doi.org/10.1063/1.870782.

      [13] Gold SH, Hardesty DL, Kinkead AK, Barnett LR & Granatstein VL, “High gain 35-GHz free electron laser amplifier experimentâ€, Physical review letters, Vol. 52, No. 14, (1984), p. 1218-1221. https://doi.org/10.1103/PhysRevLett.52.1218.

      [14] Gold SH, Black WM, Freund HP, Granatstein VL & Kinkead AK, “Radiation growth in a millimetre-wave free electron laser operating in the collective Regimeâ€, Physics of Fluids, Vol. 27, No. 3, (1984), p. 746-754. https://doi.org/10.1063/1.864650.

      [15] Gold SH, Freund HP & Bowie, “Free electron laser with tapered axial magnetic fieldâ€, The United States of America as represented by the Secretary of the Navy, Washington, DC, (1987), Patent Number: 4,644,548.

      [16] Orzechowski TJ, Anderson BR, Fawley WM, Prosnitz D, Scharlemann ET & Yarema SM, “High gain and high extraction efficiency from a free electron laser amplifier operating in the millimetre wave regimeâ€, Nuclear Instruments and Methods in Physics Research, Vol. A, No. 250, (1986), p. 144-149.

      [17] Orzeehowski TJ, Anderson BR, Clark JC, Fawley WM, Paul AC, Prosnitz D, Scharlemann ET & Yarema SM, Physical review letters, Vol. 57, No. 17, (1986).

      [18] Freund HP, “Comparison of free-electron laser amplifiers based on a step-tapered optical klystron and a conventional tapered wigglerâ€, physical review special topics- accelerators and beams, Vol.16, 060701, (2013).

      [19] Wang XJ, Freund HP, Harder D, Miner WH, Jr. Murphy JB, Qian H, Shen Y & Yang X, Physical review letters, Vol. 9, No. 103, (2009), 154801. https://doi.org/10.1103/PhysRevLett.103.154801.

      [20] Freund HP & Ganguly AK, “Nonlinear Simulation of a High-power, Collective Free Electron Laserâ€, IEEE Transactions on plasma science, Vol. 20, No. 3, (1992). https://doi.org/10.1109/27.142826.

      [21] Khodyachykh S, Brunken M, Genz H, Graf HD, Hessler C, Richter A, Wesp T, Asgekar V, Saldin E, Schneidmiller E & Yurkov M, “Observation of an FEL efficiency increase caused by magnetic field tapering of the undulator,†Nuclear Instruments and Methods in Physics Research, Vol.A, No. 530, (2004), p. 205-216.

      [22] Chung TH, Kim SH & Lee JK, “Simulation of tapered FEL amplifiers in millimetre and infrared regionsâ€, Nuclear Instruments and Methods in Physics Research, Vol.A, No. 331, (1993), p. 482-486.

      [23] J. Gardelle J, Labrouche J & Taillandier PLe,†Free electron laser simulations: Effects of beam quality and space charge,†Physical Review, Vol. 50, No. 6, (1994).

      [24] Parker RK, Jackson BH, Gold SH, Freund HP, Granatstein VL, Efthimion PC, Herndon M & Kinkead AK, “Axial Magnetic-Field Effects in a Collective-Interaction Free Electron Laser at Millimetre Wavelengthsâ€, Physical Review Letters, Vol. 48, No. 4, (1982). https://doi.org/10.1103/PhysRevLett.48.238.

      [25] Ted Scharlemann, “Physics of the Free Electron Laser,†Report: E&TR, (1986), pp. 11.

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    Gopal, R., Kumar Jain, P., & Kumar Jain, P. (2018). Effect of axial magnetic field tapering on whistler-pumped FEL amplifier in collective Raman regime operation. International Journal of Engineering & Technology, 7(4), 2044-2050. https://doi.org/10.14419/ijet.v7i4.15298