• J. Kim, G. Kim, J. Kim, S.H. Yoo
  KERI, Changwon

Using the non­lin­ear in­ter­ac­tion be­tween the high power laser and the plas­ma, we can gen­er­ate strong ac­cel­er­a­tion field, called the laser wake field ac­cel­er­a­tion. The plas­ma den­si­ty is very cru­cial to gen­er­ate high en­er­gy elec­tron. In this work, we stud­ied the ef­fect of the plas­ma den­si­ty struc­ture on the ac­cel­er­at­ed elec­tron en­er­gy. We used 20 TW, 40 fs laser sys­tem to gen­er­ate the plas­ma wake­field. A gas jet was used as a tar­get. The plas­ma den­si­ty was con­trolled by the back pres­sure of the gas noz­zle and mea­sured by the in­ter­fer­om­e­ter. The ac­cel­er­at­ed elec­tron en­er­gy was mea­sured using the elec­tron en­er­gy spec­trom­e­ter with 0.5 T mag­net. The bunch charge was mea­sured in­te­grat­ed charge trans­former (ICT). When the plas­ma den­si­ty is uni­form, 2×10¹⁹ cm^-3 we can gen­er­ate 200 MeV elec­tron beam with bunch charge 33 pC. The elec­tron beam di­ver­gence was less than 5 de­gree. If there ex­ists the down­ward den­si­ty tramp, the elec­tron en­er­gy is only 50 MeV. The PIC sim­u­la­tion also in­di­cates that if there is den­si­ty ramp struc­ture, the elec­tron is not ac­cel­er­at­ed well. In this pre­sen­ta­tion, the over­all ex­per­i­men­tal and sim­u­la­tion re­sults are pre­sent­ed.