using the double-pulse drive technique Ceri. M. Brenner, PhD student - - PowerPoint PPT Presentation

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using the double-pulse drive technique Ceri. M. Brenner, PhD student - - PowerPoint PPT Presentation

May 05, 2023 253 likes •517 views

Modification of laser driven ion beams by using the double-pulse drive technique Ceri. M. Brenner, PhD student University of Strathclyde Central Laser Facility, RAL 4 th EMMI workshop on plasma physics May 2011, Darmstadt Ion acceleration

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4th EMMI workshop on plasma physics May 2011, Darmstadt

  • Ceri. M. Brenner, PhD student

University of Strathclyde Central Laser Facility, RAL

Modification of laser driven ion beams by using the double-pulse drive technique

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What is it?

Ion acceleration driven by a double-pulse drive configuration

How does it work? How is it useful? Experimental results

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Laser-plasma accelerators

Compact, bright sources of:

  • High energy electrons
  • Gamma rays
  • XUV and x-ray radiation
  • Ions
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Ion beam cancer therapy Proton probing (field measurements) Radiography (density measurements) Injection into conventional accelerators Production of isotopes Fast ignition fusion Proton heating Industrial (lithography) Ep > ~ 100 MeV

Applications

Ep ~ 10 MeV

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SLIDE 5

High flux of medium energy (3-15 MeV) protons

Ion beam cancer therapy Proton probing (field measurements) Radiography (density measurements) Injection into conventional accelerators Production of isotopes Fast ignition fusion Proton heating Industrial (lithography) Ep > ~ 100 MeV

Applications

Ep ~ 10 MeV

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SLIDE 6

+ + +

Ponderomotive electron acceleration

  • +

+ + + + +

Target Normal Sheath Acceleration (TNSA) Electron sheath Protons (and other ions)

  • +

+ + +

plasma (a) (b) (c) time

Double pulse mechanism

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SLIDE 7

“Spectral control in proton acceleration with multiple laser pulses”, A.P.L.Robinson et al, Plasma Phys. Control. Fusion 49 (2007) 373–384 single drive pulse double drive pulse PIC

Proton energy (MeV)

Vlasov

Proton energy (MeV)

Multi-Pulse Sheath Acceleration (MPSA)

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SLIDE 8

pp/mpc pp/mpc

  • controlled initial pulse initiates TNSA of ions and protons
  • density modulation of protons builds up ahead carbon front
  • increase in Te caused by 2nd (main) drive pulse
  • surge of higher energy protons across ion front
  • high accelerating fields at ion/proton boundary

Multi-Pulse Sheath Acceleration (MPSA)

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0.01 0.1 1 1 2 3

Conversion efficiency (%) Pulse delay (ps)

0.1:1 ratio 0.4:1 ratio

x2.5 enhancement x3.3 enhancement

100 µm Au foils, Vulcan Petawatt, high contrast (with plasma mirror) “Spectral enhancement in the double pulse regime of laser proton acceleration”, K.Markey et al, PRL, 105, 195008, (2010)

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SLIDE 10

t = t0-250fs

  • Protons
  • Ions

1D PIC simulations

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SLIDE 11

t = t0-150fs

  • Protons
  • Ions

1D PIC simulations

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SLIDE 12

t = t0-50fs

  • Protons
  • Ions

1D PIC simulations

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SLIDE 13

t = t0+50fs

  • Protons
  • Ions

1D PIC simulations

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SLIDE 14

t = t0+150fs

  • Protons
  • Ions

1D PIC simulations

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SLIDE 15

t = t0+250fs

  • Protons
  • Ions

1D PIC simulations

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SLIDE 16

t = t0+350fs

  • Protons
  • Ions

Surge

1D PIC simulations

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SLIDE 17

Analysis in progress, not yet publishable

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SLIDE 18

100 µm

Recirculation and multi pulses?

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SLIDE 19

5 µm

L

For L < τLc/2 where L is 120 μm for τL ~ 800 fs

Recirculation of electrons

Recirculation and multi pulses?

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SLIDE 20

0.2 0.4 0.6 0.8 1 1.2

  • 3
  • 2
  • 1

1

Intensity (a.u.) Time (ps)

No prepulse 0.1:1, 1.5 ps

45 °

Calibrated radiochromic film (RCF) stack IL ~ 3.2 x 1019 W/cm2 IL1 ~ 3.2 x 1018 W/cm2 and IL2 ~ 2.9 x 1019 W/cm2

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Using thin foils to enhance conversion efficiency

  • 5 µm Au foils
  • Vulcan Petawatt
  • high contrast
  • ~180 J on target
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SLIDE 22

Using thin foils to enhance conversion efficiency

> x 100 increase

  • 5 µm Au foils
  • Vulcan Petawatt
  • high contrast
  • ~180 J on target

Analysis in progress, not yet publishable

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SLIDE 23

Development of MPSA technique

Spectral enhancement using the double pulse technique demonstrating:

  • significant flux enhancement in the thin foil (refluxing) regime

for lower energy protons

  • increase in laser-to-proton conversion efficiency compared to

thicker foils

Analysis in progress, not yet publishable

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Future direction:

  • investigate the double pulse technique for ultrashort laser

system parameters

  • conduct 2D PIC simulations to study the evolution of the sheath

field on the rear surface Spectral enhancement using the double pulse technique demonstrating:

  • significant proton flux enhancement in the thin foil (refluxing)

regime for lower energy protons

  • increase in laser-to-proton conversion efficiency compared to

thicker foils

Development of MPSA technique

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Strathclyde: C.M. Brenner, R.J. Gray, G. Scott, P. Mckenna CLF, RAL: R.H.H. Scott, K. Markey, K.L. Lancaster, D. Neely, P.A. Norreys, I.O. Musgrave, A.P.L. Robinson, J.S. Green, M. Notley, Vulcan laser staff and CLF target fabrication teams GSI, Darmstadt: O. Deppert, M. Roth IPPLM, Poland: M. Rosinski, J. Badziak, J. Wolowski LULI: H.P. Schlenvoigt, S.D. Baton CELIA: C. Beaucourt, J.J. Santos York: J. Pasley IST Lisbon: K. Li, J.R. Davies TEI, Crete: S.M. Hassan, E. Clarke, M. Tatarakis DFO, Milan: D. Batani

Thank you