Walter Guttenfelder


Magnetic field fluctuations (left) and density fluctuations (right) from microtearing mode turbulence simulated using GYRO, projected inside NSTX-U (with help from Filippo Scotti, LLNL) 		Princeton Plasma Physics Laboratory
Room B256
P.O. Box 451
Princeton, NJ 08543

Phone: (609) 243-2426
email: wgutten at pppl dot gov



I am a staff physicist (formerly a post-doc) working on NSTX-Upgrade at Princeton Plasma Physics Laboratory (PPPL) .

Before joining NSTX, I was a post-doc at the Centre for Fusion, Space & Astrophysics at the University of Warwick.

I received my PhD working on the Helically Symmetric Experiment (HSX) stellarator in the Electrical Engineering Deparment at the U. of Wisconsin-Madison.

Before fusion, I worked in the Flame Diagnostics Laboratory in the Mechanical Engineering Department at Purdue University.

I received my undergraduate degree in electrical engineering at Milwaukee School of Engineering.

Movies from non-linear simulations using GYRO (with help from Bill Davis)

The following simulations are run in the local limit, i.e. no equilibrium profile variations.

Microtearing mode simulation based on NSTX 120968A02 (t=0.56 s, r/a=0.6)
The simulation does not include toroidal flow & flow shear

Quicktime movie (~35 MB) of delta-Br perturbations (Gauss)
Quicktime movie (~50 MB) of delta-ne perturbations (dn/n0)
Quicktime movie (~54 MB) of both delta-ne (dn/n0) and delta-Br (Gauss) perturbations

ITG simulation based on MAST 22807F03 (t=0.25 s, r/a=0.6)
The simulation includes toroidal flow & flow shear

Quicktime movie (~157 MB) of delta-ne perturbations (dn/n0)
Shorter movie (~22 MB) of delta-ne perturbations (dn/n0)


Recent presentations

Containing a star on earth: understanding turbulence at 100 million degrees (talk slides, pdf) (talk video link) (links to videos used in talk: 1 2 3 4 5 )
January 11, 2014, PPPL Science on Saturday Lecture Series
(Related, phenomenal nature time-lapse illustrating turbulence in various places (0:14-0:20, 0:44-0:53, 1:05-1:07, 1:52-1:55, 2:23-2:31, 2:52-2:55) vimeo link )

Gyrokinetic predictions of momentum and impurity transport in NSTX (poster slides, pdf)
55th American Physical Society - Division of Plasma Physics, Denver, CO, Nov. 11-15, 2013

Progress in simulating turbulent electron thermal transport in NSTX (talk slides, pdf)
24th IAEA Fusion Energy Conference, San Diego, CA, Oct. 8-13, 2012

Other talks & posters

Publications

Spherical tokamak papers

2013

Progress in simulating turbulent electron thermal transport in NSTX
W. Guttenfelder, J.L. Peterson, J. Candy, S.M. Kaye, Y. Ren, R.E. Bell, G.W. Hammett, B.P. LeBlanc, D.R. Mikkelsen, W.M. Nevins, H. Yuh, Nucl. Fusion 53, 093022 (2013) (pdf)

The dependence of H-mode energy confinement and transport on collisionality in NSTX
S.M. Kaye, S. Gerhardt, W. Guttenfelder, R. Maingi, R.E. Bell, A. Diallo, B.P. LeBlanc, M. Podesta, Nucl. Fusion 53, 063005 (2013) (pdf)

Electron-scale turbulence spectra and plasma thermal transport responding to continuous ExB shear ramp-up in a spherical tokamak
Y. Ren, W. Guttenfelder, S.M. Kaye et al. Nucl. Fusion 53, 083007 (2013) (pdf)

Edge microstability of NSTX plasmas without and with lithium-coated plasma-facing components
J. Canik, W. Guttenfelder et al., Nucl. Fusion 53, 113016 (2013) (pdf)

Core transport of lithium and carbon in ELM-free discharges with lithium wall conditioning in NSTX
F. Scotti et al., Nucl. Fusion 53, 083001 (2013) (pdf)

Progress in characterization of the pedestal stability and turbulence during the edge-localized-mode cycle on National Spherical Torus Experiment
A. Diallo, et al., Nucl. Fusion 53, 093026 (2013) (pdf)

Measurements and simulations of low-wavenumber pedestal turbulence in the National Spherical Torus Experiment
D.R. Smith et al., Nucl. Fusion 53, 113029 (2013) (pdf)

Overview of physics results from the conclusive operation of the National Spherical Torus Experiment
S.A Sabbagh et al., Nucl. Fusion 53, 104007 (2013) (pdf)

Recent progress in the NSTX/NSTX-U lithium programme and prospects for reactor-relevant liquid-lithium based divertor development
M. Ono et al., Nucl. Fusion 53, 113030 (2013) (pdf)

A sensitivity assessment of millimeter-wave polarimetry for measurement of magnetic fluctuations associated with microtearing modes in NSTX-U
J. Zhang, N.A. Crocker, W.A. Peebles, T.A. Carter, W. Guttenfelder, Plasma Phys. Control. Fusion 55, 045011 (2013) (pdf)

Microtearing modes in spherical and conventional tokmamaks
S. Moradi, I. Pusztai, W. Guttenfelder, T. Fulop, A. Mollen, Nucl. Fusion 53, 063025 (2013) (pdf)

Characterization and parametric dependencies of low wavenumber pedestal turbulence in the National Spherical Torus Experiment
D.R. Smith, R.J. Fonck, G.R. McKee, D.S. Thompson, R.E. Bell, A. Diallo, W. Guttenfelder, S.M. Kaye, B.P. LeBlanc, M. Podesta, Phys. Plasmas 20, 055903 (2013) (pdf)

Observation of ion scale fluctuations in the pedestal region during the edge-localized-mode cycle on the National Spherical Torus Experiment
A. Diallo, G.J. Kramer, D.R. Smith, R. Maingi, R.E. Bell, W. Guttenfelder, B.P. LeBlanc, M. Podesta, G.R. McKee, R. Fonck, Phys. Plasmas 20, 012505 (2013) (pdf)

2012

Simulation of microtearing turbulence in NSTX
W. Guttenfelder, J. Candy, S.M. Kaye, W.M. Nevins, E. Wang, J. Zhang, R.E. Bell, N.A. Crocker, G.W. Hammett, B.P. LeBlanc, D.R. Mikkelsen, Y. Ren, H. Yuh, Phys. Plasmas 19, 056119 (2012) (pdf)

Scaling of linear microtearing instability for a high collisionality NSTX discharge
W. Guttenfelder, J. Candy, S.M. Kaye, W.M. Nevins, R.E. Bell, G.W. Hammett, B.P. LeBlanc, H. Yuh, Phys. Plasmas 19, 022506 (2012) (pdf)

Experimental study of parametric dependence of electron-scale turbulence in a spherical tokamak
Y. Ren, W. Guttenfelder, S.M. Kaye, E. Mazzucato, R.E. Bell, A. Diallo, C.W. Domier, B.P. LeBlanc, K.C. Lee, D.R. Smith, H. Yuh, Phys. Plasmas 19, 056125 (2012) (pdf)

Suppressing electron turbulence and triggering internal transport barriers with reverse magnetic shear in NSTX
J.L. Peterson, R. Bell, J. Candy, W. Guttenfelder, G.W. Hammett, S.M. Kaye, B. LeBlanc, D.R. Mikkelsen, D.R. Smith, H. Yuh, Phys. Plasmas 19, 056120 (2012) (pdf)

Overview of the physics and engineering design of NSTX Upgrade
J.E. Menard et al., Nucl. Fusion 52, 083015 (2012) (pdf)

2011

Electromagnetic transport from microtearing mode turbulence
W. Guttenfelder, J. Candy, S.M. Kaye, W.M. Nevins et al., Phys. Rev. Lett. 106, 155004 (2011) (pdf)

Resolving electron scale turbulence in spherical tokamaks with flow shear
W. Guttenfelder and J. Candy, Phys. Plasmas 18, 022506 (2011) (pdf)

Density gradient stabilization of electron temperature gradient driven turbulence in a spherical tokamak
Y. Ren, S.M. Kaye, E. Mazzucatto, W. Guttenfelder et al., Phys. Rev. Lett. 106, 165005 (2011) (pdf)

Electron heat transport from stochastic fields in gyrokinetic simulations
E. Wang, W.M. Nevins, J. Candy, D.R. Hatch, P.W. Terry, W. Guttenfelder, Phys. Plasmas 18, 056111 (2011) (pdf)

Edge transport and turbulence reduction with lithium coated plasma facing components in the National Spherical Torus Experiment
J. Canik, R. Maingi, S. Kubota et al., Phys. Plasmas 18, 056118 (2011) (pdf)

Collisionality and safety factor scalings of H-mode energy transport in MAST spherical tokamak
M. Valovic, R.J. Akers, M.F.M. DeBock et al., Nucl. Fusion 51, 073045 (2011) (pdf)

Plasma rotation and transport in MAST spherical tokamak
A.R. Field, C. Michael, R.J. Akers et al., Nucl. Fusion 51, 063006 (2011) (pdf)

Overview of physics results from NSTX
R. Raman, J.-W. Ahn, J.P. Allain, et al., Nucl. Fusion 51, 094011 (2011) (pdf)

Overview of physics results from MAST
B. Lloyd, R.J. Akers, F. Alladio, et al., Nucl. Fusion 51, 094013 (2011) (pdf)

Identification of microtearing modes below the ion gyroscale in the National Spherical Torus Experiment
D.R. Smith, W. Guttenfelder, B.P. LeBlanc and D.R. Mikkelsen, Plasma Phys. Control. Fusion 53, 035013 (2011) (pdf)

2009

Gyrokinetic simulations of spherical tokamaks
C.M. Roach, I.G. Abel, R.J. Akers et al., Plasma Phys. Control. Fusion 51, 124020 (2009) (pdf)

Stellarator papers

Simulating gyrokinetic microinstabilities in stellarator geometry with GS2
J.A. Baumgaertel, E.A. Belli, W. Dorland, W. Guttenfelder, G.W. Hammett, D.R. Mikkelsen, G. Rewoldt, W.M. Tang, P. Xanthopoulos, Phys. Plasmas 18, 122301 (2011) (pdf)

Internal electron transport barrier due to neoclassical ambipolarity in the Helically Symmetric Experiment
J. Lore, W. Guttenfelder, A. Briesemeister et al., Phys. Plasmas 17, 056101 (2010) (pdf)

Edge turbulence measurements in the electron-heated Helically Symmetric Experiment plasmas
W. Guttenfelder, D.T. Anderson, F.S.B. Anderson et al., Phys. Plasmas 16, 082508 (2009) (pdf)

Energetic-electron-driven instability in the Helically Symmetric Experiment
C.B. Deng, D.L. Brower, B.N. Breizman et al., Phys. Rev. Lett. 103, 025003 (2009) (pdf)

Effect of quasihelical symmetry on trapped-electron mode transport in the HSX stellarator
W. Guttenfelder, J. Lore, D.T. Anderson et al., Phys. Rev. Lett. 101, 215002 (2008) (pdf)

Experimental tests of quasisymmetry in HSX
J.N. Talmadge, F.S.B. Anderson, D.T. Anderson et al., Plasma and Fusion Research 3, S 1002 (2008) (pdf)

Overview of recent results from HSX
D.T. Anderson, A. Abdou, A.F. Almagri et al., Fusion Science and Technology 50, 171 (2006)

Comparison of Langmuir and emissive probes as diagnostics for turbulence studies in the low-temperature plasma of the torsatron TJ-K
N. Mahdizadeh, F. Greiner, M. Ramisch et al. Plasma Phys. Control. Fusion 47, 569 (2005) (pdf)

Utility of a baffled Langmuir probe for applications to edge plasma and turbulence characterization in stellarator plasma
W. Guttenfelder, C. Lechte, M.E. Koepke and V.I. Demidov Rev. Sci. Instrum. 75, 3622 (2004). (pdf)

Comparison of electron cyclotron heating results in the helically symmetric experiment with and without quasi-symmetry
K.M. Likin, A. Abdou, A.F. Almagri et al., Plasma Phys. Control. Fusion 45, A133 (2003) (pdf)

Combustion papers

Hydroxyl time series and recirculation in turbulent nonpremixed swirling flames
W.A. Guttenfelder, M.W. Renfro, N.M. Laurendeau, J. Ji, G.B. King and J.P. Gore, Combustion and Flame 147, 11 (2006) (pdf)

Hydroxly time-series measurements and simulations for turbulent premixed jet flames in the thickened preheat regime
W.A. Guttenfelder, G.B. King, J.P. Gore, N.M. Laurendeau and M.W. Renfro, Combustion and Flame 135, 381 (2003) (pdf)

Scalar time-series measurements in Turbulent CH4/H2/N2 nonpremixed flames: OH
M.W. Renfro, W.A. Guttenfelder, G.B. King and N.M. Laurendeau Combustion and Flame 123, 389 (2000) (pdf)