Author: Sabia, E.
Paper Title Page
MOP080
 Two Color Experiments at SPARC: External and Intra-bunch Seeding  
 
  • D. Alesini, M.P. Anania, M. Bellaveglia, M. Castellano, E. Chiadroni, D. Di Giovenale, G. Di Pirro, M. Ferrario, A. Gallo, G. Gatti, R. Pompili, S. Romeo, V. Shpakov, C. Vaccarezza, F. Villa
    INFN/LNF, Frascati (Roma), Italy
  • M. Artioli
    ENEA-Bologna, Bologna, Italy
  • A. Bacci, A.R. Rossi
    Istituto Nazionale di Fisica Nucleare, Milano, Italy
  • M.C. Carpanese, F. Ciocci, G. Dattoli, E. Di Palma, L. Giannessi, A. Petralia, E. Sabia, I.P. Spassovsky
    ENEA C.R. Frascati, Frascati (Roma), Italy
  • A. Cianchi
    INFN-Roma II, Roma, Italy
  • F. Filippi, A. Giribono
    INFN-Roma, Roma, Italy
  • L. Innocenti
    Università di Roma II Tor Vergata, Roma, Italy
  • N.S. Mirian, V. Petrillo
    Universita' degli Studi di Milano & INFN, Milano, Italy
  • A. Mostacci
    Rome University La Sapienza, Roma, Italy
  • J.V. Rau
    ISM-CNR, Rome, Italy
  
  The FEL-SPARC operation with two bunches at different energies has been characterized using different tools. The effect of the e-beam matching on the SASE operation has been explored by controlling the transport with an ad hoc developed control system, allowing either the transport in matching conditions and in different configurations. Since the two bunches have, at the entrance of the undulator, different phase space characteristics we used this effect as a knob to enhance or suppress one or the other FEL mode. We investigated the effect of seeding on both frequencies and observed beating waves, furthermore we observed effects of intra-bunch seeding when only one of the modes is seeded.  
 
MOP091
 Laser Heater and Seeded Free Electron Laser: Comments on Recent FERMI Experimental Results  
 
  • G. Dattoli, E. Sabia
    ENEA C.R. Frascati, Frascati (Roma), Italy
  • V. Petrillo
    Universita' degli Studi di Milano & INFN, Milano, Italy
  
  In this paper we consider the effect of laser heater on a seeded Free Electron Laser. We develop a model embedding the effect of the energy modulation induced by the heater with those due to the seeding. The present analysis is compatible with the experimental results obtained at FERMI displaying secondary maxima with increasing heater intensity. The problem has been considered ab-inito, by developing a numerical code based on the solution of the Liouville equation ruling the phase space evolution of the e-beam undergoing the various dynamical stages: Heating, Acceleration, Seeding. The treatment developed in the paper confirms and extends previous analyses and put in evidence further effects which can be tested in future experiments.  
 
TUP048
 Thoughts on the New Technologies for Compact FEL Devices  
 
  • S. Biedron, J. Einstein, S.V. Milton
    CSU, Fort Collins, Colorado, USA
  • G. Dattoli, E. Di Palma, E. Sabia, I.P. Spassovsky
    ENEA C.R. Frascati, Frascati (Roma), Italy
  • V. Petrillo
    Universita' degli Studi di Milano, Milano, Italy
  • J.V. Rau
    ISM-CNR, Rome, Italy
  
  The possibility to merge different solutions exploiting wave undulators, laser plasma acceleration and other schemes, allows the design of compact Free Electron Laser (FEL) sources operating in the extreme UV-X-ray region of the spectrum. Newly developed high peak power lasers have opened indeed effective possibilities of driving coherent light sources operating with laser plasma accelerated beams and wave undulators. We combine different ideas including also the concept of sheared beam configuration to achieve compact and reliable FEL devices. We finally comment on the perspective use of Radio Frequency (RF) undulators, which seems to be fairly good candidates for opening a new technological strategy for the design of FEL oscillators, including bi-harmonic and multi-frequency operation.  
 
WEA02
 Free Electron Laser Oscillator: Short Pulses, Mode Locking, Harmonic Generation and Tapering  
 
  • G. Dattoli, E. Sabia
    ENEA C.R. Frascati, Frascati (Roma), Italy
  • S. Biedron, S.V. Milton
    CSU, Fort Collins, Colorado, USA
  • V. Petrillo
    Universita' degli Studi di Milano, Milano, Italy
  • P.J.M. van der Slot
    Mesa+, Enschede, The Netherlands
  
  In Free Electron Laser oscillators the growth of the intracavity laser power determines the most interesting aspects of the system dynamics. In the case of short pulses operation the system undergoes genuine mode-locking mechanisms, which provide a wealth of interesting phenomena associated with the possibility of generating very short pulses. We explore the mechanisms of superradiance in FEL operating in the over-saturated regime and analyze the emerging short pulse structures and the relevant physical meaning. We also explore the pulse shape of the higher order harmonics generated in this regime and the possibility of modelling the pulse width and power by suitable combination of cavity length control and of undulator tapering.  
slides icon Slides WEA02 [13.588 MB]