magnetic reconnection and turbulence in stellar-convective
TRANSCRIPT
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Magnetic Reconnection and Turbulence in Stellar-Convective-Zone-Relevant
Laboratory Plasmas
Jack D. Hare
MAGPIE
MAGPIE: S. V. Lebedev, L. G. Suttle, S. N. Bland, T. Clayson, J. W. D. Halliday, S. Merlini, D. R. Russell, F. Suzuki-Vidal, E. R. Tubman, V. Valenzuela-Villaseca
CERBERUS: R. A. Smith, S. Eardley, T. Robinson, N. StuartGORGON: J. Chittenden, N. Niasse
with N. F. Loureiro (MIT) and A. Ciardi (Sorbonne)
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Summary
[email protected] PPPL 2020 2
Magnetic Reconnection with Plasmoids MHD Turbulence
New Diagnostics for Turbulence PUFFIN: A new pulser at MIT
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Current sheet
BB
Magnetic Reconnection
[email protected] PPPL 2020
Prediction: 1000 yrs. Reality: 10 minutes!
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Plasmoids Lead to Fast Reconnection and Anomalous Heating
Stronglysheared flows
Multiple current sheets
Overview of recent theory:Loureiro, N. F., & Uzdensky, D. A. (2015). PPCF, 58, 014021
BB
Current sheet
[email protected] PPPL 2020
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Plasmoids Lead to Fast Reconnection and Anomalous Heating
Stronglysheared flows
Multiple current sheetsBB
Current sheet
[email protected] PPPL 2020
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The Convective Zone is a Collisional Plasma (and so is a Z-Pinch)
โข Collisionless: Solar Flares, MRX, TREX
[email protected] PPPL 2020
๐ฟ โซ ๐๐๐ >๐
๐๐๐โซ
๐
๐๐๐โซ
๐ฃ๐๐๐๐๐
๐ฟ โซ๐
๐๐๐โซ
๐
๐๐๐> ๐๐๐ >
๐ฃ๐๐๐๐๐
โข Collisional: Convective zone, Z-pinch
D. D. Ryutov, IEEE TPS (2015)
Kelvinsong / CC BY-SA
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Outline
โขWhat is magnetic reconnection?
โขReconnection and Diagnostics on the MAGPIE generator
โขAnomalous heating and the Plasmoid Instability
โขCreating turbulence through flux tube merging
โขDiagnostics for turbulence
โข The PUFFIN facility
Pulsed Power Driven Reconnection, [email protected] 8
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Laboratory Reconnection Experiments
[email protected] PPPL 2020
Reconnection Layer
Laserspot
BubbleExpansion
Magnetic Ribbon
Magnetically Driven:B=0.03 T, ne=5x1013 cm-3,
V=10 km/s, L= 10 cmTe= 10 eV, Ti= 10 eV
ฮฒth<<1, ฮฒdyn<<1Long lasting
Laser Driven:B=50 T, ne=7x1019 cm-3,V=500 km/s, L= 0.1 cm,Te= 650 eV, Ti= 250 eV
ฮฒth>>1, ฮฒdyn>>1Transient
Pulsed Power Driven:B=3 T, ne=5x1017 cm-3,V=50 km/s, L= 1 cm
Te= 100 eV, Ti= 500 eV,
ฮฒth โผ 1, ฮฒdyn โผ 1Long lasting
Reconnection layer
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The MAGPIE Pulsed Power Generator
โข Constructed 1993
โข 4 Marx banks: 300 kJ
โข 1.4 MA peak current
โข 250 ns rise time
โข 1 TW into 1 cm3
MAGPIE
Load goes here
[email protected] PPPL 2020
Lebedev et al, Rev. Mod. Phys (2019)
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Plasma Source: Exploding Wire Array
[email protected] PPPL 2020 11
Current
I=1.4 MA, 240 ns rise time
Dime for scale
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Plasma Source: Exploding Wire Array
[email protected] PPPL 2020 12
Current
B
V
I=1.4 MA, 240 ns rise time
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Magnetic Reconnection Setup: Double Exploding Wire Arrays
1.4 MA
13
Suttle, L.G. et al. PRL 2016Hare, J. D. et al. PRL 2017Suttle, L.G. et al. PoP 2017Hare, J. D. et al. PoP 2018Hare, J. D. et al. PoP 2018
โข Sustained flows
โข Quasi-2D
โข Collisional
โข No guide field
Pulsed Power Driven Reconnection, [email protected]
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Magnetic Reconnection Setup: Double Exploding Wire Arrays
โข Sustained flows
โข Quasi-2D
โข Collisional
โข No guide field
Suttle, L.G. et al. PRL 2016Hare, J. D. et al. PRL 2017Suttle, L.G. et al. PoP 2017Hare, J. D. et al. PoP 2018Hare, J. D. et al. PoP 2018
14Pulsed Power Driven Reconnection, [email protected]
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Diagnostic Setup
17
y
x
y
x
G. F. Swadling et al. RSI (2014)
Pulsed Power Driven Reconnection, [email protected]
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Diagnostic Setup
18
y
x
y
x
G. F. Swadling et al. RSI (2014)
Pulsed Power Driven Reconnection, [email protected]
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Diagnostic Setup
19
z
x
z
x
y
x
y
x
G. F. Swadling et al. RSI (2014)
Pulsed Power Driven Reconnection, [email protected]
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End on Electron Density (Laser Interferometry)
Pulsed Power Driven Reconnection, [email protected]
y
x 20
Wires
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End on Electron Density (Laser Interferometry)
Pulsed Power Driven Reconnection, [email protected]
y
x 21
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End on Electron Density (Laser Interferometry)
Pulsed Power Driven Reconnection, [email protected]
y
x
A plasmoid
22
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Pulsed Power Driven Reconnection, [email protected]
Magnetic Field Profile (Faraday Rotation Imaging)
23
z
x
10 mm
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Magnetic Field Profile (Faraday Rotation Imaging)
24
z
x Pulsed Power Driven Reconnection, [email protected]
10 mm
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Magnetic Field Profile (Faraday Rotation Imaging)
B B
25
z
x Pulsed Power Driven Reconnection, [email protected]
๐ผ(๐ฅ, ๐ง) โ เถฑ๐๐๐ฉ. ๐๐
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B B
Magnetic Field Profile (Faraday Rotation Imaging)
Harris Sheet:
1 mm
z
x
G. F. Swadling et al. RSI (2014)
๐ผ(๐ฅ, ๐ง) โ เถฑ๐๐๐ฉ. ๐๐
26Pulsed Power Driven Reconnection, [email protected]
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Velocity and Temperature (Thomson Scattering)
27
Fibre Optic Bundle
Fibre Optic Bundle
Pulsed Power Driven Reconnection, [email protected]
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Overall shift: Vfi
Collective scattering from Ion Acoustic Waves
Velocity and Temperature (Thomson Scattering)
28
Fibre Optic Bundle
Fibre Optic Bundle
Pulsed Power Driven Reconnection, [email protected]
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29
Fibre Optic Bundle
Fibre Optic Bundle
Pulsed Power Driven Reconnection, [email protected]
Separation: ZTe
Overall shift: Vfi
Collective scattering from Ion Acoustic Waves
Velocity and Temperature (Thomson Scattering)
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30
Fibre Optic Bundle
Fibre Optic Bundle
Pulsed Power Driven Reconnection, [email protected]
Width: Ti
Separation: ZTe
Overall shift: Vfi
Collective scattering from Ion Acoustic Waves
Velocity and Temperature (Thomson Scattering)
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31
Fibre Optic Bundle
Fibre Optic Bundle
Pulsed Power Driven Reconnection, [email protected]
Width: Ti
Separation: ZTe
Overall shift: Vfi
Collective scattering from Ion Acoustic Waves
Velocity and Temperature (Thomson Scattering)
[100 km/s]
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Velocity and Temperature (Thomson Scattering)
ฮป0
32
Fibre Optic Bundle
2 mm
Pulsed Power Driven Reconnection, [email protected]
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Velocity and Temperature (Thomson Scattering)
ฮป0
33
Fibre Optic Bundle
2 mm
Cold (50 eV)Fast movingฮฮป=0.6 ร
V=50 km/s
Hot (600 eV)Stationary
ฮฮป
Pulsed Power Driven Reconnection, [email protected]
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Velocity and Temperature (Thomson Scattering)
ฮป0
34
Fibre Optic Bundle Cs= 30 km/s, VA= 70 km/s
2 mm
Pulsed Power Driven Reconnection, [email protected]
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Velocity and Temperature (Thomson Scattering)
ฮป0
35
Fibre Optic Bundle Cs= 30 km/s, VA= 70 km/s
2 mm
Pulsed Power Driven Reconnection, [email protected]
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Power Balance in the Reconnection Layer
Pulsed Power Driven Reconnection, [email protected] 36
๐๐๐๐ฟโ ๐ธ๐๐๐ + ๐ธ๐๐๐ + ๐ธ๐กโ,๐ + ๐ธ๐กโ,๐ โ ๐๐๐ข๐ก๐ฟโ ๐ธ๐๐๐ + ๐ธ๐กโ,๐ + ๐ธ๐กโ,๐~50% ~25% ~25% ~40% ~60%
2ฮด
2L ๐๐๐
๐๐๐ข๐ก
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Anomalous Heating in the Reconnection Layer
Pulsed Power Driven Reconnection, [email protected] 37
๐๐๐๐ฟโ ๐ธ๐๐๐ + ๐ธ๐๐๐ + ๐ธ๐กโ,๐ + ๐ธ๐กโ,๐ โ ๐๐๐ข๐ก๐ฟโ ๐ธ๐๐๐ + ๐ธ๐กโ,๐ + ๐ธ๐กโ,๐~50% ~25% ~25% ~40% ~60%
ฯ๐ฃ๐๐ ๐ โ 800 ns
ฯ๐๐๐ โ 350 ns
ฯ๐๐ฅ๐ โ 50 ns
Classical heating is too slow:
ฯ๐๐ฅ๐ โช ฯ๐ฃ๐๐ ๐, ฯ๐๐๐ 2ฮด
2L ๐๐๐
๐๐๐ข๐ก
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Anomalous Heating in the Reconnection Layer
[email protected] JPP 2020
๐๐๐๐ฟโ ๐ธ๐๐๐ + ๐ธ๐๐๐ + ๐ธ๐กโ,๐ + ๐ธ๐กโ,๐ โ ๐๐๐ข๐ก๐ฟโ ๐ธ๐๐๐ + ๐ธ๐กโ,๐ + ๐ธ๐กโ,๐~50% ~25% ~25% ~40% ~60%
ฯ๐ฃ๐๐ ๐ โ 800 ns
ฯ๐๐๐ โ 350 ns
ฯ๐๐ฅ๐ โ 50 ns
Classical heating is too slow:
ฯ๐๐ฅ๐ โช ฯ๐ฃ๐๐ ๐, ฯ๐๐๐ 2ฮด
2L ๐๐๐
๐๐๐ข๐ก
Need a faster mechanism:Plasmoids?
38
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Outline
โขWhat is magnetic reconnection?
โขReconnection and Diagnostics on the MAGPIE generator
โขAnomalous heating and the Plasmoid Instability
โขCreating turbulence through flux tube merging
โขDiagnostics for turbulence
โข The PUFFIN facility
Pulsed Power Driven Reconnection, [email protected] 39
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Plasmoids Visible in Electron Density Maps
Pulsed Power Driven Reconnection, [email protected] 40
Region of enhanced density (a โplasmoidโ): Vy=130 km/s
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Uniformity of Inflows
Pulsed Power Driven Reconnection, [email protected] 41
Uniform inflow density near layer
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Plasmoids lead to fast reconnection and anomalous heating
Multiple current sheets
Overview of recent theory:Loureiro, N. F., & Uzdensky, D. A. (2015). PPCF, 58, 014021
BB
Current sheet
Plasmoid instability depends on:โข ๐ = ๐0๐ฟ๐๐ด/๐๐๐
[Lundquist number]โข ๐ฟ/๐๐
[current sheet length]
48Pulsed Power Driven Reconnection, [email protected]
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Stronglysheared flows
Multiple current sheets
Regimes of the Plasmoid instability: Collisional MHD
49Pulsed Power Driven Reconnection, [email protected]
Collisional MHD
Plasmoids
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PlasmoidsStronglysheared flows
Multiple current sheets
Regimes of the Plasmoid instability: The Semi-Collisional Regime
50Pulsed Power Driven Reconnection, [email protected]
Include two-fluid effects
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The Semi-Collisional Plasmoid Instability
Pulsed Power Driven Reconnection, [email protected] 51
Baalrud et al. PoP 2011
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Outline
โขWhat is magnetic reconnection?
โขReconnection and Diagnostics on the MAGPIE generator
โขAnomalous heating and the Plasmoid Instability
โขCreating turbulence through flux tube merging
โขDiagnostics for turbulence
โข The PUFFIN facility
Pulsed Power Driven Reconnection, [email protected] 52
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Flux Tube Merging
[email protected] PPPL 2020
Shading: out of plane currentBlack lines: magnetic flux surfaces
From Zhou, Y. et al. (2004). Rev Mod Phys, 76(4), 1015โ1035
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Flux Tube Merging
[email protected] PPPL 2020
From Zhou, Y. et al. (2004). Rev Mod Phys, 76(4), 1015โ1035
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Flux Tube Merging
[email protected] PPPL 2020
From Zhou, Y. et al. (2004). Rev Mod Phys, 76(4), 1015โ1035
Anisotropy
Power Spectra
Intermittency
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Pulsed-power driven Flux Tube Merging
Wire arrays produce flux tubes during initial ablation
From: Martin et al. PoP 2010
Wire cores
[email protected] PPPL 2020
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Flux tubes merge on axis to form a turbulent column
Pulsed-power driven Flux Tube Merging
[email protected] PPPL 2020
Flux tubes
From: Martin et al. PoP 2010
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Optical Self Emission: Formation of a Turbulent Column
Axial imaging
Wires
5 mm
Long lasting, confined column
[email protected] PPPL 2020
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Optical Self Emission: Formation of a Turbulent Column
Axial imaging
Wires
5 mm
[email protected] PPPL 2020
Long lasting, confined column
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Dimensionless Parameters
Wires
L = 5 mm
DimensionlessParameters
EstimatedParameters
140 nsne= 5 x 1018 cm-3
Te = 100 eVTi = 200 eVB = 5 TV = 200 km/s
ฮปei/L โ 0.01ฮฒ โ 1Re โ 2500ReM โ 250Pr < 0.1
[email protected] PPPL 2020
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Axial Interferometry shows cellular structures
Wires
s0327_185 mm
355 nm laser probing: 200 ns after current startCellular structures
[email protected] PPPL 2020
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Side on Shadwography shows cellular structures
[email protected] JPP 2020
Long lasting, confined column
Cellular turbulentstructures
Imploding Wire Array
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Outline
โขWhat is magnetic reconnection?
โขReconnection and Diagnostics on the MAGPIE generator
โขAnomalous heating and the Plasmoid Instability
โขCreating turbulence through flux tube merging
โขDiagnostics for turbulence
โข The PUFFIN facility
Pulsed Power Driven Reconnection, [email protected] 63
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B
V
Pulsed Power Driven Turbulence, [email protected] 64
A simple experiment: Plasma flow into a planar obstacle
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Imaging Refractometry: Density Fluctuations
[email protected] PPPL 2020
Flow
https://arxiv.org/abs/2007.04682
Flow into planar obstacle
B
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Imaging Refractometry: Density Fluctuations
[email protected] PPPL 2020
Flow
https://arxiv.org/abs/2007.04682
Flow into planar obstacleReverse shock forms
B
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Planar shock experiment: Aluminium, stable
[email protected] PPPL 2020
Flow
https://arxiv.org/abs/2007.04682
Flow into planar obstacleReverse shock forms
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Planar shock experiment: Tungsten, Turbulent
[email protected] PPPL 2020
Flow
https://arxiv.org/abs/2007.04682
Flow into planar obstacle???? forms
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Ray d
eflection
angle (m
rad)
30
-30
Space
0
[email protected] PPPL 2020
Flow
Planar shock experiment: Tungsten, Turbulent
Flow
https://arxiv.org/abs/2007.04682
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Flow
Planar shock experiment: Tungsten, Turbulent
Space [email protected] PPPL 2020
Flow
https://arxiv.org/abs/2007.04682
Ray d
eflection
angle (m
rad)
30
-30
0
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Measuring the Spectrum of Deflection Angles
Undeflected raysDeflected rays
[email protected] PPPL 2020
Flow
0.8 0.6 0.4 0.2Intensity (a.u.)
Flow
https://arxiv.org/abs/2007.04682
Ray d
eflection
angle (m
rad)
30
-30
0
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Measuring the Spectrum of Deflection Angles
Undeflected raysDeflected rays
L
n
n
n
Ln
cr
e
cr
e
22
1
=
FWHM D โ 0.75 degrees
Spatialscale
Deflectionangle
Need a theory to link distribution of total deflection angles to the spectrum of density fluctuations
Random walk -> Gaussian
[email protected] PPPL 2020
Flow
0.8 0.6 0.4 0.2Intensity (a.u.)
https://arxiv.org/abs/2007.04682
Ray d
eflection
angle (m
rad)
30
-30
0
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Measuring the Spectrum of Deflection Angles
Undeflected raysDeflected rays
L
n
n
n
Ln
cr
e
cr
e
22
1
=
FWHM D โ 0.75 degrees
Spatialscale
Deflectionangle
Need a theory to link distribution of total deflection angles to the spectrum of density fluctuations
Random walk -> Gaussian
But - deflection spectrum notGaussian!
[email protected] PPPL 2020
Flow
0.8 0.6 0.4 0.2Intensity (a.u.)
https://arxiv.org/abs/2007.04682
Ray d
eflection
angle (m
rad)
30
-30
0
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Faraday Rotation Imaging: Out of Plane Magnetic Fields
77
No axial fields in inflowsAxial interferometry
Out of planefields
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Local measurements from Thomson Scattering
78
Ion Feature:Collective scattering, 28-points
Electron Feature:Collective and non-collective scattering
Probebeam
Bulk Flow,Electron and iontemperatures
Electron temperature,density
[email protected] PPPL 2020
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Outline
โขWhat is magnetic reconnection?
โขReconnection and Diagnostics on the MAGPIE generator
โขAnomalous heating and the Plasmoid Instability
โขCreating turbulence through flux tube merging
โขDiagnostics for turbulence
โข The PUFFIN facility
Pulsed Power Driven Reconnection, [email protected] 79
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Long drive times required to study instabilities and turbulence
[email protected] JPP 2020
Flux tube mergingPlasmoid Instability
5 mm
Wires
5 mm
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Pulsed Power Driven Reconnection, [email protected] 81
Emperor Penguin:
4 ft/1.2 m
1.5 MA peak current, 1.5 ยตs rise time
[MAGPIE: 1.4 MA, 0.25 ยตs]
Starting January 2021 at MIT
Instabilities and turbulence need time to develop.
Vacuum coaxtransmission lines
Vacuum chamber
PUFFIN: A long drive pulser for fundamental plasma physics
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Conclusions
โข Reconnection and turbulence in collisional HED plasmas
โข Sub-Alfvรฉnic reconnection, anomalous heating, plasmoid unstable
โข Magnetised turbulence with Pr < 1, ๐ฝ โผ 1
โข New diagnostics to study turbulence in unprecedented detail
โข PUFFIN: a new long drive pulser for magnetised HED plasmas at MIT
[email protected] PPPL 2020 82