beam plasma physics experiments at orion l.
Download
Skip this Video
Loading SlideShow in 5 Seconds..
Beam Plasma Physics Experiments at ORION PowerPoint Presentation
Download Presentation
Beam Plasma Physics Experiments at ORION

Loading in 2 Seconds...

play fullscreen
1 / 27

Beam Plasma Physics Experiments at ORION - PowerPoint PPT Presentation


  • 726 Views
  • Uploaded on

2 nd ORION Workshop February 18-20, 2003 Beam Plasma Physics Experiments at ORION Mark Hogan SLAC 2 nd ORION Workshop February 18-20, 2003 Outline Large Fields Show Large Promise in Beam-Plasma Physics Highlights of Recent Experiments Example Experiments

loader
I am the owner, or an agent authorized to act on behalf of the owner, of the copyrighted work described.
capcha
Download Presentation

PowerPoint Slideshow about 'Beam Plasma Physics Experiments at ORION' - oshin


An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript
outline

2nd ORION Workshop February 18-20, 2003

Outline
  • Large Fields Show Large Promise in Beam-Plasma Physics
  • Highlights of Recent Experiments
  • Example Experiments
  • Look towards the Working Group asking how some of the open
  • questions might be addressed at ORION
slide3

Recent Results III: Promise and Challenge

  • E-157 & E-162 have observed a wide range of phenomena with both
  • electron and positron drive beams:

Electron Beam Refraction at the Gas–Plasma Boundary

e- & e+ Focusing

X-ray Generation

Wakefield acceleration

qµ1/sinf

q≈f

o BPM Data

– Model

Phys. Rev. Lett. 2002, 2003

To Science 2003

Phys. Rev. Lett. 2002

Nature 2002

  • ORION researchers over the past few years, developed a facility for doing unique physics, and also many of the techniques and the expertise necessary for conducting next experiments
slide4

evolves to

Concepts For Plasma-Based Accelerators

Pioneered by J.M.Dawson

Research into “advanced” technologies and concepts that could provide the next innovations needed by particle physics. In many cases one is applying or extending physics and technology that is its own discipline to acceleration (ex. plasma physics, laser physics…). Active community investigating high-frequency rf, two-beam accelerators, laser accelerators, and plasma accelerators.

  • Laser Wake Field Accelerator(LWFA)
  • A single short-pulse of photons
  • Plasma Beat Wave Accelerator(PBWA)
  • Two-frequencies, i.e., a train of pulses
  • Self Modulated Laser Wake Field Accelerator(SMLWFA)
  • Raman forward scattering instability
  • Plasma Wake Field Accelerator(PWFA)
  • A high energy electron (or positron) bunch
slide5

But can it lead to…?

A 100 GeV-on-100 GeV e-e+ ColliderBased on Plasma Afterburners

3 km

30 m

Afterburners

LENSES

50 GeV e-

50 GeV e+

e-WFA

e+WFA

IP

slide6

Many Issues Need to Be Addressed First

1. Development of plasma sources capable of producing densities

> 1016 e-/cm3 over distances of several meters.

2. Quantify limitations of plasma lenses due to chromatic and spherical

aberrations.

3. Stable propagation through such a long high-density ion column –

beam matching and no limits due to electron hose instability.

4. Preservation of beam emittance

5. Accelerating gradients orders of magnitude larger than those studied

to date – via shorter bunches and optimized profiles.

6. Beam loading of the plasma wake with ~ 50% charge of the drive

beam

In fact, these issues will need to be addressed for many applications of beam plasma interactions

Many advances in recent years…

slide7

E-150: Plasma Lens for Electrons and Positrons

Phys. Rev. Lett. 87, 244801 (2001)

Built on early low-energy demonstration experiments in early to mid-nineties:

FNAL (1990), JAPAN (1991), UCLA (1994)…

Demonstrated plasma lensing of 28.5GeV beams

slide8

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

+

+

+

+

+

+

+

+

+

+

+

+

+

+

+

-

+

+

+

+

+

+

+

+

+

+

+

+

+

+

+

-

-

-

-

-

-

-

-

-

+

+

+

+

+

+

+

+

+

+

+

+

+

+

+

+

-

-

+

+

+

+

+

-

+

+

+

+

+

-

+

+

+

+

+

+

+

+

+

+

+

+

+

+

+

-

-

-

-

+

+

+

+

+

+

+

+

+

+

+

+

+

+

+

-

-

-

-

-

-

-

-

-

-

-

electron beam

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

Ez

E-157, E-162, E-164 and E-164X:

All (e- or e+) Beam Driven PWFA

LINEAR PWFA SCALING

Decelerating

Accelerating

Ez: accelerating field

N: # e-/bunch

sz: gaussian bunch length

kp: plasma wave number

np: plasma density

nb: beam density

Short bunch!

m

m Forand

or

m However, when nb > np, non-linear or “blow-out” regime

m Scaling laws valid?

slide9

E-162, E-164 & E-164X:

Common Experimental Apparatus

A quick reminder of how we do these experiments in the FFTB…

Located in the FFTB

Ionizing

Laser Pulse

(193 nm)

Streak Camera

(1ps resolution)

e- or e+

∫Cdt

Li Plasma

ne≈2·1014 cm-3

L≈1.4 m

X-Ray

Diagnostic

N=2·1010

sz=0.6 mm

E=30 GeV

Cerenkov

Radiator

Optical Transition

Radiators

Spectrometer

Dump

25 m

FFTB

Not to scale!

slide10

ne=0

ne≈1014 cm-3

2mm

• Ideal Plasma Lens in Blow-Out Regime

e-

2mm

• Plasma Lens with Aberrations

e+

Plasma Focusing of

Electrons and Positrons

• OTR images ≈1m from plasma exit

Note: enx>eny

slide11

Experiments at ORIONmay address limitations of plasma lenses

High de-magnification plasma lens could help determine the ultimate limitations of plasma lenses. For a plasma lens with length equal to the focal length the de-magnification is given by:

Want small emittance, large initial beam size, but enough beam density for blow-out

Limitations due to geometric and chromatic aberrations: &

J. J. Su et al Phys. Rev. A 41, 3321 (1990)

slide12

E-157

E-162 Run 2

Plasma OFF

sx (µm)

Phase Advance  ne1/2L

Phase Advance  ne1/2L

Stable Propagation Through

An Extended Plasma

Beam matched to the plasma when:

Physical Review Letters88, 154801 (2002)

- Matching minimizes spot size variations and stabilize hose instability

- Places a premium on getting small spots

slide13

Stable Propagation Part II

Electron Hose Instability?

No significant instability observed in E-162 with

np up to 21014 cm-3, and L=1.4 m

- Hose instability grows as1exp((kbL)2/3), where kb=wp/(2g)1/2c=(npe2/e0me 2g)1/2c

  • E-162:np=21014 cm-3, L=1.4 m => e4.5=92
  • E-164:np=61015 cm-3, L=0.3 m => e5.4=227
  • E-164X:np=21017 cm-3, L=0.06 m => e5.4=227

no significant growth expected (?)

  • Theory assumes a preformed channel, neglects return currents…
  • Simulations include these effects and also predict little growth2

Phys. Rev. Lett. 67, 991 (1991)

Phys. Rev. Lett. 88 , 125001 (2002)

slide14

E-157: Electron Beam Refraction

At Plasma–Gas Boundary

Asymmetric

Channel

Beam Steering

Symmetric

Channel

Beam Focusing

Core

+

+

+

+

+

+

+

+

+

+

+

+

+

+

+

+

+

+

+

+

+

+

+

+

+

+

+

+

+

+

+

+

+

+

+

+

+

+

+

+

+

+

+

+

e-

+

+

+

+

+

+

Plasma, ne

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

Head

q

f

rc=a(nb/ne)1/2rb

qµ1/sinf

• Vary plasma – e- beam angle f

using UV pellicle

• Beam centroid displacement

@ BPM6130, 3.8 m from the

plasma center

q≈f

o BPM DATA

Impulse Model

P. Muggli et al., Nature 411, 2001

slide15

Experiment

(Cherenkov

images)

Laser off

Laser on

3-D OSIRIS

PIC Simulation

Refraction of an Electron Beam:

Interplay between Simulation & Experiment

l 1st 1-to-1 modeling of meter-scale experiment in 3-D!

P. Muggli et al., Nature 411, 2001

slide16

E-162: X-Ray Emission from

Betatron Motion in a Plasma Wiggler

Central Photon Energy = 14.2 keV

Number of Photons = 6x105

Peak Spectral Brightness = 7x1018

[#/(sec-mrad2-mm2-0.1%)]

Phys. Rev. Lett. 88, 135004 (2002)

slide17

SM-LWFA electron energy spectrum

S

h

o

t

1

2

(

1

0

k

G

)

6

S

h

o

t

2

6

(

1

0

k

G

)

1

0

S

h

o

t

2

9

(

5

k

G

)

S

h

o

t

3

3

(

5

k

G

)

S

h

o

t

3

9

(

2

.

5

k

G

)

5

1

0

S

h

o

t

4

0

(

2

.

5

k

G

)

4

1

0

Relative # of electrons/MeV/Steradian

3

1

0

6

8

1

0

2

0

4

0

6

0

8

0

1

0

0

2

0

0

E

l

e

c

t

r

o

n

e

n

e

r

g

y

(

i

n

M

e

V

)

Plasmas Have Demonstrated Abilityto Support Large Amplitude Accelerating Electric Fields

100 MeV Laser Wakefield Results

A. Ting et al NRL

200 MeV Laser Wakefield Results

at Ecole Poly., France

Accelerating Gradient

~200 GeV/m!

Accelerating Gradient

> 100 GeV/m

V. Malka et al., Science 298, 1596 (2002)

Need guiding or other technique to extend interaction distance beyond a few mm

slide18

Particles in the core nearly de-accelerated to zero!

Accelerated Tail Particles

Average Gradient ~ 70 MeV/m

PWFA Acceleration Experiments at ANL-AWA and FNL-A0

Head

Tail

Simulation

N. Barov et al, PAC-2001-MOPC010, FERMILAB-CONF-01-365, Dec 2001. 3pp

slide19

Beam Driven PWFA

Single Bunch Energy Transformer

OSIRIS Simulation

Experimental Data

Head

Head

  • Average measured energy loss (slice average): 159±40 MeV
  • Average measured energy gain (slice average): 156 ±40 MeV

(≈1.5108 e-/slice)

slide20

A Few Examples of How

ORION Might Help Address Some of These Issues

flexible electron source opportunities for plasma wakefield acceleration

10

0

Gradient (GeV/m)

-10

Flexible Electron Source  Opportunities for Plasma Wakefield Acceleration

PWFA with optimized drive bunch for transformer ratios (>2)

  • Bunch compression (R56 < 0) produces a ramped profile with a sharp cutoff  high transformer ratio
drive and witness beam production
Drive and Witness Beam Production
  • Compressed, high-current 350 MeV drive pulse
  • Narrow energy spread, 60 MeV witness pulse, with continuously variable delay

0-120 ps Vernier Delay chicane

Combiner chicane

(also compresses drive pulse)

Fast kicker

and septum magnet

HIGH ENERGY HALL

NLCTA

1 1 2 simulation vs linear superposition

Use Witness Bunch Capability to Study EffectsOf beam Loading on Accelerating Wake

1+1 ≠ 2:Simulation vs. Linear Superposition

Linearsuperposition

Nonlinear wake

2nd beam charge density

1st beam charge density

Nonlinear wake

focusing force also effected by beam loading

…and the Transverse (Focusing) Wake

Focusing Force Also Effected By Beam Loading

Linear superposition of focusing force

Focusing force on r=0.5c/Wp

Simulation result

2 beam charge densities

slide25

Ion Channel Laser1:Proof of Principle at Optical Wavelengths

“Accelerator-based synchrotron light sources play a pivotal role in the U.S. scientific community2. Free-electron lasers (FEL’s) can provide coherent radiation at wavelengths across the electromagnetic spectrum, and recently there has been growing interest in extending FEL’s down into the X-rays to provide researchers tools to understand the nature of proteins and chromosomes. … there is exciting potential for innovative science in the range of 8-20 keV, especially if a light source can be built with a high degree of coherence, temporal brevity, and high pulse energy. To date, the most promising candidate for such a source is a linac-driven X-ray FEL. It would be a unique instrument capable of opening new areas of research in physics, materials, chemistry and biology.

Build on the experience of E-157/E-162/E-164 towards an ICL

  • Move beyond spontaneous x-rays to stimulated emission via the ICL (analogous to an FEL with plasma wiggler)
  • Requires many betatron oscillations therefore lower energy beam with high density plasma
    • 60MeV, 20cm long plasma of 6x1015 density for visible
    • 300MeV, 1.5m long plasma of 4x1014 density for ultraviolet (80nm)
  • ICL potential advantage over FEL:
    • Short wavelength with relatively lower gamma – less linac, better coupling
    • Shorter period and stronger wigglers via plasma ion column

1 D. H. Whittum et al Phys. Rev. Lett. 64, 2511 (1990).

2Report of The Basic Energy Sciences Advisory Committee Panel on Novel Coherent Light Sources,

Workshop at Gaithersburg Maryland, January 1999.

http://www.er.doe.gov/production/bes/BESAC/NCLS_rep.PDF

slide26

Electron Beam Refraction at the Gas–Plasma Boundary

e- & e+ Focusing

X-ray Generation

Wakefield acceleration

qµ1/sinf

q≈f

o BPM Data

– Model

Beam Plasma Experiments:

Observed a wide range of phenomena but still much to do

  • Focusing of electron beams and stable propagation through an extended plasma
  • Electron beam deflection analogous to refraction at the gas-plasma boundary
  • X-ray generation due to betatron motion in the blown-out plasma ion column
  • Large gradients (>100GeV/m) over mm scale distances
  • Smaller gradients (~100MeV/m) over meter scale distances

Still much to do:

  • Quantify limits for plasma lenses due to chromatic and spherical aberrations
  • Test for continued robustness against instabilities such as electron hose
  • > GeV/m acceleration via shorter bunches and tailored longitudinal profiles
  • Plasma source development: higher densities over several meters
  • Extend radiation generation from spontaneous to stimulated emission via ICL
  • Load the plasma wake and preserve focusing properties of the ion channel
  • Load the plasma wake for acceleration with narrow energy spread and high extraction efficiency
beam plasma working group

2nd ORION Workshop February 18-20, 2003

Beam-Plasma Working Group

Redwood Room “?”

Prof. Tom Katsouleas WG Leader

  • We will focus on:
  • Plasma wakefield physics
  • Plasma lenses
  • Beam quality
  • Radiation generation
  • Instabilities
  • Shaped beams
  • Beam loading
  • Simulation and theory needs.
  • Particularly relevant are:
  • Ideas for experiments at ORION
  • Ideas for diagnostics, instruments and models that could support/improve experiments.
  • Requirements for diagnostics, instruments, beams and models (whether or not you have an idea of how to make them) that would enable/improve experiments.