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]