Plasma physics experiments at Z6:

Interaction of heavy ions with laser driven plasma

Ø energy loss of projectile ions in ideal / non-ideal plasma

Ø charge state distribution of ions penetrating plasma

Ø charge exchange processes in ionized matter

Ø probing of plasma properties by energy loss of heavy ions

 


 

Various plasma heating schemes

Direct heating

high Te

highly ionized

strong gradients

/fileadmin/_migrated/pics/ExpZ6_target1ab.png
Hohlraum heating


moderate Te

 moderate ionized

 homogeneous

/fileadmin/_migrated/pics/ExpZ6_target2ab.png

 

Various targets

Directly heated foil targets:

hot (Te > 200 eV)

plasma highly / fully ionized

plasma fast expanding

energy loss in ideal plasma

/fileadmin/_migrated/pics/ExpZ6_target3a.jpg

Hohlraum target with foil/foam:

homogeneous

moderate temperature

slow expansion

energy loss in non-ideal plasma

/fileadmin/_migrated/pics/ExpZ6_target3b.jpg

Direct heated foams:

smoothing of laser energy

slow expansion

super sonic ionization

/fileadmin/_migrated/pics/ExpZ6_target3c.jpg

Cryogenic H-target:

fully ionized plasma target

Charge exchange by free electrons

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Recent results:
Energy loss and charge state distribution of Ar ions at 4 MeV/u penetrating a laser generated Carbon plasma

Projectile: 36Ar

Target: laser heated Carbon foil

Laser: nhelix (NdYAG)

Energy: 4 MeV/u

Thickness: 0.5 µm (100 µg/cm²)

Wavelength: 1064 nm

Initial charge state: 16+

Plasma density: 1018 – 1022 e/cm3

Energy: 50 J

 

Plasma temperature: up to 250 eV

Pulse length: 10 ns

   

Intensity: 5·1011 W/cm2

/fileadmin/_migrated/pics/ExpZ6_1.png
Fig.1: Energy loss of Ar ions penetrating the laser heated carbon foil/plasma. Shown are four experimental results, where the delay between the laser and ion pulse has been shifted. The solid lines in the bottom of the figure show the temporal laser pulse profile. The 0 in the time scale was set to the beginning of the laser pulse.
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Fig. 2: Calculated charge state distributions of Ar ions interacting with a carbon plasma at t=12 ns after the beginning of the laser heating process. The blue curve in the right picture is the mean charge state resulting from the distribution in the left graph.

Collaboration: TU-Darmstadt; Uni-Frankfurt; VNIIEF-Sarov; ITEP-Moscow; LPI-Moscow