Recent theoretical advances. on plasma based tools. for HEDP

Transcription

1 GoLP/IPFN Instituto Superior Técnico Recent theoretical advances J. Vieira on plasma based tools Instituto de Plasmas e Fusão Nuclear Instituto Superior Técnico Lisbon, Portugal golp grupo de lasers grupo de lasers e plasmas for HEDP

2 National Academy of Sciences (US) report states importance of plasma acceleration to the future of high energy physics. physics of matter under high energy density conditions. The following list of questions is not intended to be complete but rather to be illustrative of important questions of high intellectual value in high energy density physics: How does matter behave under conditions of extreme temperature, pressure, density, and electromagnetic fields? What are the opacities of stellar matter? What is the nature of matter at the beginning of the universe? How does matter interact with photons and neutrinos under extreme conditions? What is the origin of intermediate-mass and high-mass nuclei in the universe? Can nuclear flames (ignition and propagating burn) be created in the laboratory? Can high-yield ignition in the laboratory be used to study aspects of supernovae physics, including the generation of high-z elements? Can the mechanisms for formation of astrophysical jets be simulated in laboratory experiments? Can the transition to turbulence, and the turbulent state, in high energy density systems be understood experimentally and theoretically? What are the dynamics of the interaction of strong shocks with turbulent and inhomogeneous media? Will measurements of the equation of state and opacity of materials at high temperatures and pressures change models of stellar and planetary structure? Can electron-positron plasmas relevant to gamma-ray bursts be created in the laboratory? Can focused lasers boil the vacuum to produce electron-positron pairs? Can macroscopic amounts of relativistic matter be created in the laboratory and will it exhibit fundamentally new collective behavior? Can we predict the nonlinear optics of unstable multiple and interacting beamlets of intense light or matter as they filament, braid, and scatter? Can the ultraintense field of a plasma wake be used to make an ultrahighgradient accelerator with the luminosity and beam quality needed for applications in high energy and nuclear physics? Can high energy density beam-plasma interactions lead to novel radiation sources?

3 Surfing a sea wave and plasma acceleration Boat expels water Surfers slides in the boat-driven sea wave Gravity pulls water back

4 Plasma based acceleration uses intense beams to drive plasma waves Electron bunch is like a surfer Electron acceleration Laser * or particle beam ** is like a boat in the sea Radiation pressure expels plasma electrons Plasma wave is like a sea wave Ions attract electrons *T. Tajima and J.M. Dawson Phys. Rev. Lett (1979) **P. Chen, J. Dawson et al Phys. Rev. Lett (1985)

5 Electrons gain energy while crossing the wakefield Movie in a frame that travels at c Jorge Vieira for the Jorge AWAKE Vieira collaboration APPLAuSE HEDP IMFP, Madrid IST, October April, 7th 21, 2016

6 New plasma spring co-moving frame coordinate leads to dramatic changes on the plasma electron dynamics Plasma waves RF frequency device Eaccel ~ n0 1/2 [cm -3 ] V/cm Eaccel ~100 MV/m 100 microns 100 centimeters

7 One of the goals for this technology is to design and construct a plasma based linear collider. Laser Gas jet Capillary TeV electrons 100 modular stages 1-10 km 1 TeV 1 TeV Plan for a plasma based linear collider Courtesy: Wim Leemans (LBL) Figure 6. A 2-TeV electro driven plasma acceleratio electron arm could be a s each with its own laser. A wave in each module s 1-m formed plasma. Bunched gain 10 GeV by riding chain begins w from a g p TeV positrons Laser Laser Laser 100 modular stages 10 GeV Gas jet Positron production target e e +

8 Since plasma electrons are free plasma waves can be bent in nearly any possible way

9 Ultra-intense structured laser pulses could open up the access to unexplored degrees of freedom Main properties of OAM OAM lasers are described by LG modes Helical wavefronts Helical phase l r r 2 a r (r) =c l,p exp w 0 w 2 0 2r + il L l 2 p w0 2 Laser electric field isosurfaces Donut-shaped intensity profiles Normalization Generalized Laguerre Polynomial Spiralling wave-vector Transverse slice of laser envelope L. Allen et al, PRA (1992)

10 Achieving high gradient positron acceleration possible in doughnut plasma waves Linear doughnut wakefields Non-linear doughnut bubbles (a) E [m c /e] 1 e p Laguerre- Gaussian laser Hollow electron bunch Hollow bubble doughnut plasma wave Positrons accelerate here J. Vieira et al. PoP and PRL (2014).

11 Antimatter catches a wave in experiments at SLAC S. Corde et al, Multi-gigaelectronvolt acceleration of positrons in a self-loaded plasma wakefield, Nature 524, (2015) Positron driven acceleration Beam and plasma dynamics 1.Positron beam sucks in plasma electrons 2.Beam front decelerates (energy conservation) 3.Strong beam self-evolution 4.A doughnut-like plasma wave eventually forms 5.A focusing electron filament forms on axis. 6.Positrons at the back accelerate

12 Twisted plasma accelerators could produce beams with non-trivial spatiotemporal correlations plasma wave with orbital angular momentum spiralling electron beam Spatiotemporal correlated betatron x-ray beams could be used to probe matter in radically new ways! Light spring

13 High harmonic generation - extreme nonlinear optics < 10 fs duration Broad frequency range UV - kev Another view on HHG: the medium joins n photons with frequency ω into a single photon with frequency nω Adapted from M. Mournaine

14 New plasma science using high harmonics Extreme nonlinear optics in plasmas Practical, table-top, coherent light sources at > kev photon energies High resolution coherent plasma imaging Creation and probing of warm dense plasmas using high flux harmonics with 50 nm spatial resolution, picometer depth resolution, and femto- atto-second time resolution Adapted from M. Mournaine

15 Vortex light high harmonic generation will open the access to super-high spatial resolutions SLM gas jet slit MCP (a) Impart OAM to pump beam (b) Source chamber Spectrometer (c) grating Conservation of energy and momentum:! n photons with frequency ω and OAM combined into a single photon with frequency nω and OAM n Gariepy et al. PRL (2015)

16 The orbital angular momentum of light can be used to enhance the spatial resolution Petal spacing decreases with l Petal beam l =12 =8 =4 =2 and and l l =-8 =-4 =-2 =-12 Combine OAM pairs (±") r0 ~ w0 l 1/2 exp(i"φ)+exp(-i"φ) 2 ~ 4 cos("φ) 2 dmin ~!0 Petal spacing defines the optical resolution of these beams

17 Reach the ultimate spatial resolution requires independent control of the orbital angular momentum What is the highest OAM possible? Dispersion of plane e.m. wave: ω 2 = c 2 k 2 HHG is far from theoretical limits Non-plane e.m. wave: ω 2 = c 2 k0 2 +c 2 k 2 Paraxial approximation (rays travel at low angles): After HHG with OAM: l nl Theoretical limit: l max w0 2 k0 2 n 2 k ~ /r 0 k0 r0 r0 ~ w0 l 1/2 Lobe spacing can be as small as laser wavelength l max nl Beam intensity with two OAM modes +l and -l

18 HHG combined with Raman scattering could provide lasers enabling novel views of the quantum world Initial Seed with/without OAM (a) Initial Time plasma Pump with several OAM levels Depleted pump Final Amplified Seed with high OAM harmonics OAM plasma waves 2 Stimulated Raman scattering can be used to achieve unprecedented control over the spatiotemporal structure of the laser

19 Azimuthal Fourier transform of an initially Gaussian seed shows generation of high OAM harmonics Pump with l = -3 and l = 3 OAM Fourier Transform OAM Fourier transform reveals presence of OAM harmonics Power [arb.units] Orbital Angular Momentum 20 30

20 High orbital angular momentum harmonic generation Selection rule l = lseed ± mδl Δl = lpump1-lpump2 integer m All Even Multiples of 3 Δl=1 and lseed= 0 Δl=2 and lseed = 0 Δl=3 and lseed = y [w 0 ] 0 y [w 0 ] 0 y [w 0 ] x [w 0 ] x [w 0 ] x [w 0 ]

21 All optical realisation of the Green-Tao theorem based on high OAM harmonics generation Green-Tao theorem First prime OAM harmonics There is an integer α and β such that the arithmetic progression: Power [arb.units] Prediction Pump OAM l = 4 l 1 = 3 α + β m l = 6 l 1 = -1 is a prime 3 for every integer m Prediction smaller k 7 Simulation Simulation 11 Pump OAM Orbital angular momentum

22 GoLP/IPFN Instituto Superior Técnico Conclusions Structured beams will open new frontiers in HEDP Positron acceleration in the plasma Structured plasma waves Spatiotemporally correlated betatron x-rays High orbital angular momentum harmonics generation