[Triumf-seminars] TRIUMF Accelerator Seminar today at 14:00

[TRIUMF Seminars]

Date/Time: Wed 2013-04-03 at 14:00

Location:  Auditorium          

Speaker:   Patric Muggli (MPI Munich)

Title:     Plasma Wakefield Acceleration and the AWAKE Project at CERN

Abstract: Plasma wakefield acceleration has made remarkable progress in the last ten years. Experiments at SLAC have shown that an energy gain by trailing electrons of 42GeV in only 85cm of plasma is possible. This corresponds to an average accelerating gradient larger than 50GeV/m sustained over a meter-scale plasma. These results were possible only because ultra-relativistic, short (~100fs), high peak current (~10kA) electron bunches, focusable to ~10µm transverse size, are available at SLAC. However, these bunches only carry ~60J of energy, thereby limiting the ultimate energy gain by a trailing bunch. Therefore this electron beam driven plasma wakefield scheme will have to resort to staging to reach the energy frontier (0.5-1TeV).
Proton bunches produced by the CERN SPS (450GeV, 1011 p+) and LHC (7TeV) carry 7 to 110kJ. If used as plasma wakefield drivers they could take an incoming electron bunch with a few GeV to the energy frontier in a single plasma section, as demonstrated in simulations in Caldwell et al., Nature Physics 5, 363 (2009). However, proton bunches available today are long, typically 10cm rms length in the CERN case and would drive low amplitude wakefields in low density plasmas. We are planning on using a recently proposed self-modulation instability (SMI, N. Kumar et al., Phys. Rev. Lett. 104, 255003 (2010)) to demonstrate that proton bunches can drive GV/m wakefields in plasmas in the ten meter length range. In this scheme the incoming bunch first forms a train of bunches with the periodicity of the plasma wavelength (~1.2mm typically) through the occurrence of the SMI. The train can then resonantly drive wakefields to large amplitudes. The instability can be seeded to shorten its saturation length and control the wakefields phase. A witness electron bunch can then be injected to witness the wakefields and be accelerated. The proposed experimental program is called AWAKE.
I will introduce the concept of plasma wakefield acceleration, briefly review the major experimental results obtained to date and introduce the AWAKE program as well as SMI physics experiments planned at SLAC.


Stimulants available 15 minutes before the talk.

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