UCLA and USC AARD PROGRAMS C.Joshi, W.Mori, C.Clayton(UCLA), T.Katsouleas, P.Muggli(USC) “Putting the Physics of Beams at the Forefront of Science” 50+ PRL 5 Nature 1Science 2Physics Today 25 PhDs

� Double the energy of Collider w/ short plasma sections before IP � 1 st half of beam excites wake --decelerates to 0 � 2 nd half of beams rides wake--accelerates to 2 x E o � Make up for Luminosity decrease  N 2 /  z 2 by halving  in a final plasma lens 50 GeV e - 50 GeV e + e - WFA e + WFA IP LENSES 5m PLASMA AFTERBURNER S. Lee et al., PRST-AB (2001) GRAND CHALLENGE in AARD OO

Betatron Radiation Positron Source Collimators e - Extraction e-e- z x Plasma 40 m 10 cm Bending Magnet hνhν Target 8mm  One meter long plasma of density 1e17 could produce 20 positrons/e The energy spectrum is in the 5-30 MeV range. Possibility of generating polarized positrons? D.Johnson et.al.To be submitted to PRL

Electron Cloud Formation Cloud build-up due to acceleration in beam potential and secondary emission Clouds form in positron rings via synchrotron radiation Clouds form in proton rings via halo or residual gas ionization Predicted Electron cloud density is cm -3 A head-tail type instability results in beam blow up

 Advanced Computational Modeling Program All AARD Schemes will eventually need access to a 10 GeV class electron/positron beam line.  Beam Research Facilities : SABER  Strong University-Based Research Program AARD Needs

OUR VISION  To address critical issues for realizing the promise of a plasma-based accelerator at the energy frontier in the next decade.  To Design a Hi-fidelity virtual accelerator at full scale and end-to-end.  To address critical issues for realizing the promise of a plasma-based accelerator at the energy frontier in the next decade.  To Design a Hi-fidelity virtual accelerator at full scale and end-to-end.

PLASMA WAKEFIELD ACCELERATOR Blowout regime flattens wake, reduces energy spread Unloaded wake E157,162,164(X), 167 EzEz Beam load Loaded wake N load ~30% N max 1% energy spread

MASSIVELY PARALLEL COMPUTATIONS IN AID OF PLASMA ACCELERATION RESEARCH afterburner hosing E164X OSIRIS: (Full PIC) Moving window, parallel Dynamic load balancing Field and Impact Ionization Successfully applied to full 3D modeling of LWFA and PWFA experiments QuickPIC: Highly efficient quasi-static model for beam- driven plasma accelerators Fully parallel with dynamic load balancing Ponderomotive guiding center + envelope models for laser driven ADK model for field ionization At least100x faster than full PIC.

Accelerating field 24GeV/m at the load 500 GeV Energy Gain in 20 meters! N=3x10 10 electrons N=1x10 10 electrons

E164X August Run 12GeV Energy Gain in less than 30cm !

Latest Results from E164X  First attempt at crafting two distinct bunches First bunch drives the wake while the second gains energy.  Positrons created from betatron X-rays and positron spectra measured.  Multi GeV trapped particles observed whenever the gradient exceeded 40 GeV/m.

Clear threshold Self Trapping of Plasma Electrons Trapping above a threshold accelerating field of 40 GeV/m Dark current ~ beam current (loads the wake) Trapping above a threshold accelerating field of 40 GeV/m Dark current ~ beam current (loads the wake) Trapped particle energy scales with plasma length: 30cm

What’s Next?:E167 Energy Doubling of the SLAC 28.5 GeV Beam in 60 cm Possible Plasma Length(cm) Energy Gain (GeV) If successful E167 will try doubling the 50 GeV Beam 3D OSIRIS SIMULATIONS

RAL LBL Osaka UCLA E164X ILC Current Energy Frontier ANL Plasma Accelerator Progress “Accelerator Moore’s Law” E167 O E167 O

CRITICAL R&D PATH TO PLASMA AFTERBURNER High Gradient Electron and Positron Acceleration Transverse Beam Quality (emittance preservation) –jitter and pointing,head erosion –hose instability,ion motion,scattering “Crafting” Two Bunches Nanometer Focusing,Asymmetric Beams All these issues can be addressed with SABER One-to-One PIC Simulations Capability of a Virtual One-to-One PIC Simulations Capability of a Virtual Plasma Afterburner Plasma Afterburner

Short e + pulses from SABER will give gradients of 5 GeV/m 5.7GeV in 39cm N=1.5e10 Spot Size=10 micron Bunch length=100fs Simulations:M.Zhou UCLA

Plasma Focusing to Nanometer Spot Sizes FFTB experiments have shown focusing Strengths of giga- Gauss/cm Can we focus e +,e - SABER beams to submicron dimension using plasma lenses? Can we design layered structures as lenses for obtaining nanometer spot sizes? M.Hogan et.al. PRL 03 J.Ng et al. PRL E162: Positron Focusing

PH.D STUDENTS TRAINED IN PAST FIVE YEARS Brian Duda, 2000 Mori Shuoqin Wang, 2002 Joshi Brent Blue, 2003 Joshi Catalin Filip, 2003 Joshi Ritesh Narang, 2003 Joshi Chengkun Huang, 2005Mori Advisor: Over 25 Ph.Ds granted since group ’ s inception. Faculty placed at USC, UCLA, U. Michigan/Nebraska, Florida A&M, CalState, U. Osaka 5 Student Awards including two Best Ph.D. Thesis Awards Suzhi Deng Ali Ghalam Jerry Hoffman Seung Lee Peter Lai Chiou

Statistical Data $1 million/yr average since 1987 SciDAC ~ $170 K /year Theory and Simulations NSF ~ $150 K/year UCLA, present SLAC, present SLAC, as soon as it is built 3.Users at Neptune: Joshi, Rosenzweig, Pellegrini, Muggli, Katsouleas Annual Funding: DoE HEP$490k NSF (ORION)$50k DoESciDAC$40k

CONCLUSIONS Acknowledgements:E157,162,164,164Xand167 collaborators DOE HEP,NSF,SCIDAC,USC,UCLA Exciting time for AARD DOE’s investment in AARD is beginning to pay off. The AARD community is putting the Physics of Beams at the forefront of Physics and science. Continuing access to a high energy electron and positron beams is a must for the health of the field. (Need SABER at SLAC) Plasmas are leading to well behaved optical elements of incredible power for incorporation into future HEP machines. table-top GeV class accelerators for applications other than HEP.

Conclusions AARD program is doing an excellent job in training students. Retention would be significantly improved if the National Labs were more aggressive in assisting with Permanant Residence ( Green Card)in the US. Industry is very successful with this strategy.