UCLA and USC AARD PROGRAMS

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

2. GRAND CHALLENGE in AARD PLASMA AFTERBURNER • Double the energy of Collider w/ short plasma sections before IP • 1st half of beam excites wake --decelerates to 0 • 2nd half of beams rides wake--accelerates to 2 x Eo • Make up for Luminosity decrease N2/z2 by halving  in a final plasma lens LENSES 50 GeV e- 50 GeV e+ e+WFA e-WFA O O IP 5m S. Lee et al., PRST-AB (2001)

3. Collimators Plasma Bending Magnet Target hν e- x 8mm z e- Extraction 10 cm 40 m Betatron Radiation Positron Source • 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

4. Electron Cloud Formation • Clouds form in positron rings via synchrotron radiation • Clouds form in proton rings via halo or residual gas ionization • Cloud build-up due to acceleration in beam potential and secondary emission • Predicted Electron cloud density is 105 - 107 cm-3 • A head-tail type instability results in beam blow up

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

6. 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.

7. PLASMA WAKEFIELD ACCELERATORBlowout regime flattens wake, reduces energy spread Beam load Ez Unloaded wake E157,162,164(X),167 • Loaded wake • Nload~30% Nmax • 1% energy spread

8. afterburner hosing E164X . MASSIVELY PARALLEL COMPUTATIONS IN AID OF PLASMA ACCELERATION RESEARCH 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

9. N=1x1010 electrons N=3x1010 electrons 500 GeV Energy Gain in 20 meters! Accelerating field 24GeV/m at the load

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

11. 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.

12. Self Trapping of Plasma Electrons Clear threshold • Trapping above a threshold accelerating field of 40 GeV/m • Dark current ~ beam current (loads the wake) • Trapped particle energy scales with plasma length: 5GeV @ 30cm

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

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

15. 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 Plasma Afterburner

16. 5.7GeV in 39cm Short e+ pulses from SABER will give gradients of 5 GeV/m N=1.5e10 Spot Size=10 micron Bunch length=100fs Simulations:M.Zhou UCLA

17. Plasma Focusing to Nanometer Spot Sizes FFTB experiments have shown focusing Strengths of giga-Gauss/cm M.Hogan et.al. PRL 03 J.Ng et al. PRL E162: Positron Focusing 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?

18. PH.D STUDENTS TRAINED IN PAST FIVE YEARS Advisor: • Brian Duda, 2000 Mori • Shuoqin Wang, 2002 Joshi • Brent Blue, 2003 Joshi • Catalin Filip, 2003 Joshi • Ritesh Narang, 2003 Joshi • Chengkun Huang, 2005 Mori Suzhi Deng Ali Ghalam Jerry Hoffman Seung Lee Peter Lai Chiou 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

19. Statistical Data • Funding: DOE-HEP @ $1 million/yr average since 1987 SciDAC ~ $170 K /year Theory and Simulations NSF ~ $150 K/year • Facilities: Neptune @ UCLA, 1998 - present FFTB @ SLAC, 1999 - present SABER @ SLAC, as soon as it is built • Users at Neptune: Joshi, Rosenzweig, Pellegrini, Muggli, Katsouleas • Annual Funding: • DoE HEP $490k • NSF (ORION) $50k • DoE SciDAC $40k

20. CONCLUSIONS • 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. Acknowledgements:E157,162,164,164Xand167 collaborators DOE HEP,NSF,SCIDAC,USC,UCLA

21. 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.