Steep Gradient Region Research Articles

Measurements and simulations of low-wavenumber pedestal turbulence in the National Spherical Torus Experiment

Previous pedestal turbulence measurements in the National Spherical Torus Experiment assessed the spatial and temporal properties of turbulence in the steep gradient region of H-mode pedestals during edge localized mode (ELM)-free, MHD-quiescent periods. Here, we extend the analysis to fluctuation amplitudes and compare observations to pedestal turbulence simulations. Measurements indicate normalized fluctuation amplitudes are about 1–5% in the steep gradient region. Regression analysis indicates fluctuation amplitudes scale positively with electron density gradient, collisionality, and poloidal beta, and scale negatively with magnetic shear, electron density, ion temperature gradient (ITG), toroidal flow and radial electric field. The scalings are most consistent with trapped electron mode, kinetic ballooning mode, or microtearing instabilities, but, notably, least consistent with ITG turbulence. Gyrokinetic simulations of pedestal turbulence with realistic pedestal profiles show collisional instabilities with growth rates that increase at higher density gradient and decrease at higher ITG, in qualitative agreement with observed scalings. Finally, Braginskii fluid simulations of pedestal turbulence do not reproduce scalings from measurements and gyrokinetic simulations, and suggest electron dynamics can be a critical factor for accurate pedestal turbulence simulations.

Edge microstability of NSTX plasmas without and with lithium-coated plasma-facing components

The pedestal structure in NSTX is strongly affected by lithium coatings applied to the PFCs. In discharges with lithium, the density pedestal widens, and the electron temperature (Te) gradient increases inside a radius of ψN ∼ 0.95, but is unchanged for ψN > 0.95. The inferred effective electron thermal and particle profiles reflect the profile changes: is slightly increased in the near-separatrix region, and is reduced in the region ψN < 0.95 in the with-lithium case. The profile shows a broadening of the region with low diffusivity with lithium, while the minimum value within the steep-gradient region is comparable in the two cases. The linear microstability properties of the edge plasma without and with lithium have been analysed. At the pedestal top microtearing modes are unstable without lithium. These are stabilized by the stronger density gradient with lithium, becoming TEM-like with growth rates reduced and comparable to E × B shearing rates. In the region ψN > 0.95, both the pre- and with-lithium cases are calculated to be unstable to ETG modes, with higher growth rates with lithium. Both cases are also found to lie near the onset for kinetic ballooning modes, but in the second-stable region where growth rates decrease with increasing pressure gradient.

Overview of physics results from the conclusive operation of the National Spherical Torus Experiment

Research on the National Spherical Torus Experiment, NSTX, targets physics understanding needed for extrapolation to a steady-state ST Fusion Nuclear Science Facility, pilot plant, or DEMO. The unique ST operational space is leveraged to test physics theories for next-step tokamak operation, including ITER. Present research also examines implications for the coming device upgrade, NSTX-U. An energy confinement time, τE, scaling unified for varied wall conditions exhibits a strong improvement of BTτE with decreased electron collisionality, accentuated by lithium (Li) wall conditioning. This result is consistent with nonlinear microtearing simulations that match the experimental electron diffusivity quantitatively and predict reduced electron heat transport at lower collisionality. Beam-emission spectroscopy measurements in the steep gradient region of the pedestal indicate the poloidal correlation length of turbulence of about ten ion gyroradii increases at higher electron density gradient and lower Ti gradient, consistent with turbulence caused by trapped electron instabilities. Density fluctuations in the pedestal top region indicate ion-scale microturbulence compatible with ion temperature gradient and/or kinetic ballooning mode instabilities. Plasma characteristics change nearly continuously with increasing Li evaporation and edge localized modes (ELMs) stabilize due to edge density gradient alteration. Global mode stability studies show stabilizing resonant kinetic effects are enhanced at lower collisionality, but in stark contrast have almost no dependence on collisionality when the plasma is off-resonance. Combined resistive wall mode radial and poloidal field sensor feedback was used to control n = 1 perturbations and improve stability. The disruption probability due to unstable resistive wall modes (RWMs) was surprisingly reduced at very high βN/li > 10 consistent with low frequency magnetohydrodynamic spectroscopy measurements of mode stability. Greater instability seen at intermediate βN is consistent with decreased kinetic RWM stabilization. A model-based RWM state-space controller produced long-pulse discharges exceeding βN = 6.4 and βN/li = 13. Precursor analysis shows 96.3% of disruptions can be predicted with 10 ms warning and a false positive rate of only 2.8%. Disruption halo currents rotate toroidally and can have significant toroidal asymmetry. Global kinks cause measured fast ion redistribution, with full-orbit calculations showing redistribution from the core outward and towards V∥/V = 1 where destabilizing compressional Alfvén eigenmode resonances are expected. Applied 3D fields altered global Alfvén eigenmode characteristics. High-harmonic fast-wave (HHFW) power couples to field lines across the entire width of the scrape-off layer, showing the importance of the inclusion of this phenomenon in designing future RF systems. The snowflake divertor configuration enhanced by radiative detachment showed large reductions in both steady-state and ELM heat fluxes (ELMing peak values down from 19 MW m−2 to less than 1.5 MW m−2). Toroidal asymmetry of heat deposition was observed during ELMs or by 3D fields. The heating power required for accessing H-mode decreased by 30% as the triangularity was decreased by moving the X-point to larger radius, consistent with calculations of the dependence of E × B shear in the edge region on ion heat flux and X-point radius. Co-axial helicity injection reduced the inductive start-up flux, with plasmas ramped to 1 MA requiring 35% less inductive flux. Non-inductive current fraction (NICF) up to 65% is reached experimentally with neutral beam injection at plasma current Ip = 0.7 MA and between 70–100% with HHFW application at Ip = 0.3 MA. NSTX-U scenario development calculations project 100% NICF for a large range of 0.6 < Ip(MA) < 1.35.

Flux limited schemes: Their classification and accuracy based on total variation stability regions

A classification in terms of accuracy of flux limited high resolution schemes in steep gradient region is done which is based on two different total variation (TV) stability regions. The dependence of the TV stability regions on the smoothness parameter is shown. This dependence relation relates and pave a way to define a common unified TV stability region for both class of schemes. New flux limiters, satisfying the unified TV stability region are also proposed which are robust and work efficiently for both backward (left) and forward (right) moving solution profiles. Main significant feature of this classification is that it can be used to construct hybrid schemes and improve the accuracy of all existing flux limiters based schemes. Numerical results on linear test problems are given to support the theoretical discussion.

Does the γ dose distribution comparison technique default to the distance to agreement test in clinical dose distributions?

To determine the validity of the assumption that the γ dose distribution comparison tool defaults to the distance to agreement test under conditions of clinically relevant steep dose gradients and γ test criteria. The assumption was tested by computing the angle θ between the dose axis and γ vector for clinical treatment plans. θ was a function of the evaluated dose distribution dose gradient and the ratio (α) of the dose difference to distance to agreement (DTA) criteria. Dose distributions from prostate, head and neck, and lung clinical treatment plans were examined: 50 treatment plans were selected for each of the prostate and head neck sites and 27 treatment plans were selected for lung. Dose-gradient histograms were prepared for each of the treatment plans using α = 1%/mm (e.g., 3%, 3 mm dose difference and DTA criteria, respectively). To determine how frequently different values of α were used in publications, papers that referenced the original γ paper were examined to identify the dose difference and DTA criteria used in those publications. In order to compare θ calculated using α = 1%/mm to θ for other values of α, the relationship between θ and α was determined. For most of the targets and critical structures, the maximum value of θ approached 90°, so the assumption that the γ tool defaulted to the DTA test in steep dose gradients was correct. Most of the published papers using the γ tool employed the 3%, 3 mm dose difference and DTA criteria, respectively. Most of the other evaluations used criteria such that α ≥ 1%/mm, so the conclusions relating to the examined dose distributions applied. There were a few papers employing very small values of α (including one where α = 0.17%/mm), breaking the assumption that the γ dose comparison tool defaulted to the DTA tool in steep dose gradients. Most published cases utilized values of α ≥ 1%/mm, and for those the implicit assumption that the γ dose comparison tool defaults to the DTA test in steep dose gradient regions was true. There were a few cases for which α was small enough to potentially invalidate this assumption. Care should be taken by investigators when selecting the γ test criteria to assure that the γ test will appropriately default to the DTA test in the steepest dose gradients being evaluated.

SU‐E‐T‐20: Validating That the Gamma Dose Distribution Comparison Defaults to the Distance‐To‐Agreement (DTA) Test in Steep Dose Gradients for Clinical Dose Distributions

Purpose: To test the validity of the central assumption that the gamma dose comparison test defaults to a distance‐to‐agreement (DTA) test in steep dose gradient regions of clinical dose distributions for typically employed dose difference and DTA criteria. Methods: The angle θ between the dose axis and the gamma vector was computed usingθ = tan−1(Λ), where Λ was the local dose gradient of the evaluated dose distribution. θ depended only on the ratio α between the two test criteria and its computation required only one dose distribution. While the most common test criteria were 3%/3mm (α = 1%/mm), we also evaluated 2%/3mm (α = 0.67%/mm) and 3%/2mm (α = 1.5%/mm). Clinical treatment plans were used to calculate θ using the three values of α. 50 cases of both prostate and head and neck and 27 cases for lung cancer were examined. The planning target volumes and selected critical structures were examined. The maximum values of θ were determined for these structures to determine if these maximum θ angles were close to 90 degrees for the selected a values. Results: Most examined targets and critical structures exhibited large values of θ. The exception was for some parotid glands where the doses were very low and relatively homogeneous. The fact that we found that most structures had at least some voxels with sufficiently large dose gradients to yield θ values near 90 degrees validated our hypothesis that for steep gradients, the gamma test defaulted to distance‐to‐agreement test for clinical dose gradients. Conclusion: The implicit assumption that the gamma dose comparison tool defaults to the DTA test in steep dose gradient regions was validated for prostate, had‐and‐neck, and lung cancer sites. While dose distributions from other sites have not been examined, it is likely that they too will yield similar results.

SU‐E‐J‐99: Utilizing CT Dual DFOV in Treatment Planning System

Purpose: Typically, a Display Field of View (DFOV) parameter is set to accommodate the wide part of anatomy in the scan, which is the shoulder in head and neck (HN) cases. The dual DFOV can make use of two image resolutions in one CT set. However, the Eclipse™ treatment planning system (TPS) accepts only the larger DFOV when reconstructing the body volume and thus particularly reduces in‐plane resolution of the head region. In this study, we developed a method to preserve the original resolution of head CT images. Methods: The anthromorphic phantom was scanned from head to shoulder using the GE LightSpeed RT16 CT by applying small and large DFOV to head and shoulder region, respectively. Our in‐house software enables dual DFOV CT images to be entered into Eclipse™ TPS. Basically, the software converts the pixel size of head CT images from 512 × 512 to 1024 × 1024 by expanding the DFOV outside. Results: The original and processed CT sets were loaded by Eclipse™ TPS and the differences were analyzed. Processed CT images showed two times better resolution than original CT images in head region. Distinguishing target and OAR in processed CT images is also clearer than before. We also confirmed that the mean percentage difference of CT numbers before and after processing was negligible for total phantom volume of the head region except steep gradient region which CT number changes drastically. Conclusion: The advantage of dual DFOV images was fully taken in the Eclipse™ TPS. In treatment planning, defining target and organ at risk which is the most important part for accurate treatment can be improved using high resolution dual DFOV CT images.

Global gyrokinetic simulations of the H-mode tokamak edge pedestal

Global gyrokinetic simulations of DIII-D H-mode edge pedestal show two types of instabilities may exist approaching the onset of edge localized modes: an intermediate-n, high frequency mode which we identify as the “kinetic peeling ballooning mode (KPBM),” and a high-n, low frequency mode. Our previous study [W. Wan et al., Phys. Rev. Lett. 109, 185004 (2012)] has shown that when the safety factor profile is flattened around the steep pressure gradient region, the high-n mode is clearly kinetic ballooning mode and becomes the dominant instability. Otherwise, the KPBM dominates. Here, the properties of the two instabilities are studied by varying the density and temperature profiles. It is found that the KPBM is destabilized by density and ion temperature gradient, and the high-n mode is mostly destabilized by electron temperature gradient. Nonlinear simulations with the KPBM saturate at high levels. The equilibrium radial electric field (Er) reduces the transport. The effect of the parallel equilibrium current is found to be weak.

Characterization and parametric dependencies of low wavenumber pedestal turbulence in the National Spherical Torus Experiment

The spherical torus edge region is among the most challenging regimes for plasma turbulence simulations. Here, we measure the spatial and temporal properties of ion-scale turbulence in the steep gradient region of H-mode pedestals during edge localized mode-free, MHD quiescent periods in the National Spherical Torus Experiment. Poloidal correlation lengths are about 10 ρi, and decorrelation times are about 5 a/cs. Next, we introduce a model aggregation technique to identify parametric dependencies among turbulence quantities and transport-relevant plasma parameters. The parametric dependencies show the most agreement with transport driven by trapped-electron mode, kinetic ballooning mode, and microtearing mode turbulence, and the least agreement with ion temperature gradient turbulence. In addition, the parametric dependencies are consistent with turbulence regulation by flow shear and the empirical relationship between wider pedestals and larger turbulent structures.

A well‐balanced stable generalized Riemann problem scheme for shallow water equations using adaptive moving unstructured triangular meshes

SUMMARYWe propose a well‐balanced stable generalized Riemann problem (GRP) scheme for the shallow water equations with irregular bottom topography based on moving, adaptive, unstructured, triangular meshes. In order to stabilize the computations near equilibria, we use the Rankine–Hugoniot condition to remove a singularity from the GRP solver. Moreover, we develop a remapping onto the new mesh (after grid movement) based on equilibrium variables. This, together with the already established techniques, guarantees the well‐balancing. Numerical tests show the accuracy, efficiency, and robustness of the GRP moving mesh method: lake at rest solutions are preserved even when the underlying mesh is moving (e.g., mesh points are moved to regions of steep gradients), and various comparisons with fixed coarse and fine meshes demonstrate high resolution at relatively low cost. Copyright © 2013 John Wiley &amp; Sons, Ltd.

Stress Correlation between Instrumentation and Simulation Analysis of the Die for High Pressure Die Casting

A strain gauge instrumentation trial on a high-pressure die casting (HPDC) die was compared to a corresponding simulation model using Magmasoft® casting simulation software at two strain gauge rosette locations. The strains were measured during the casting cycle, from which the von Mises stress was determined and then compared to the simulation model. The von Mises stress from the simulation model correlated well with the findings from the instrumentation trial, showing a difference of 5.5%, ∼ 10 MPa for one strain gauge rosette located in an area of low stress gradient. The second rosette was in a region of steep stress gradient, which resulted in a difference of up to 40%, ∼40 MPa between the simulation and instrumentation results. Factors such as additional loading from die closure force or metal injection pressure which are not modelled were shown to have very little influence on the stress in the die, less than 7%.

Improvements of the Vasiliev's box-scheme for transcritical flows in open channel

Vasiliev’s fully implicit finite difference box scheme, used in hydraulic engineering to simulate flood routing and overland flow, is invalid, in its usual implementation, for modelling transcritical flow. Short waves, generated near regions of steep gradients, and responsible for the often observed grid-to-grid oscillations, are not damped. In order, to suppress these spurious oscillations, which degrade and successively instabilise the solution, the adaptive smoothing approach is applied herein. The remedy confines the damping only near sharp gradients, and unaffects the regions where the flow is relatively smooth. In addition, weighted in time the spatial derivative approximations, the prevention of the dissipation in a broad spectrum of wave number, is obtained. By Fourier linear analysis, the stability, the convergence, and the variations of the time-weighted parameter, of the Courant number, of the Froude number, of the frictional parameter, and of the viscosity coefficient are investigated. Benchmark test cases, involving transcritical flow, friction, non-uniform bed slopes, and non-prismatic channels, and laboratory dam-break simulations, compared to the analytical solutions, and the experimental data, are presented.

First observation of a new zonal-flow cycle state in the H-mode transport barrier of the experimental advanced superconducting Tokamak

A new turbulence-flow cycle state has been discovered after the formation of a transport barrier in the H-mode plasma edge during a quiescent phase on the EAST superconducting tokamak. Zonal-flow modulation of high-frequency-broadband (0.05–1 MHz) turbulence was observed in the steep-gradient region leading to intermittent transport events across the edge transport barrier. Good confinement (H98y,2 ∼ 1) has been achieved in this state, even with input heating power near the L-H transition threshold. A novel model based on predator-prey interaction between turbulence and zonal flows reproduced this state well.

Global Gyrokinetic Simulation of Tokamak Edge Pedestal Instabilities

Global electromagnetic gyrokinetic simulations show the existence of near threshold conditions for both a high-n kinetic ballooning mode (KBM) and an intermediate-n kinetic version of peeling-ballooning mode (KPBM) in the edge pedestal of two DIII-D H-mode discharges. When the magnetic shear is reduced in a narrow region of steep pressure gradient, the KPBM is significantly stabilized, while the KBM is weakly destabilized and hence becomes the most-unstable mode. Collisions decrease the KBM's critical β and increase the growth rate.

In-phantom dose verification of prostate IMRT and VMAT deliveries using plastic scintillation detectors

The goal of this work was to demonstrate the feasibility of using a plastic scintillation detector (PSD) incorporated into a prostate immobilization device to verify doses in vivo delivered during intensity-modulated radiation therapy (IMRT) and volumetric modulated-arc therapy (VMAT) for prostate cancer. The treatment plans for both modalities had been developed for a patient undergoing prostate radiation therapy. First, a study was performed to test the dependence, if any, of PSD accuracy on the number and type of calibration conditions. This study included PSD measurements of each treatment plan being delivered under quality assurance (QA) conditions using a rigid QA phantom. PSD results obtained under these conditions were compared to ionization chamber measurements. After an optimal set of calibration factors had been found, the PSD was combined with a commercial endorectal balloon used for rectal distension and prostate immobilization during external beam radiotherapy. This PSD-enhanced endorectal balloon was placed inside of a deformable anthropomorphic phantom designed to simulate male pelvic anatomy. PSD results obtained under these so-called "simulated treatment conditions" were compared to doses calculated by the treatment planning system (TPS). With the PSD still inserted in the pelvic phantom, each plan was delivered once again after applying a shift of 1 cm anterior to the original isocenter to simulate a treatment setup error.The mean total accumulated dose measured using the PSD differed the TPS-calculated doses by less than 1% for both treatment modalities simulated treatment conditions using the pelvic phantom. When the isocenter was shifted, the PSD results differed from the TPS calculations of mean dose by 1.2% (for IMRT) and 10.1% (for VMAT); in both cases, the doses were within the dose range calculated over the detector volume for these regions of steep dose gradient. Our results suggest that the system could benefit prostate cancer patient treatment by providing accurate in vivo dose reports during treatment and verify in real-time whether treatments are being delivered according to the prescribed plan.

Fast visible imaging and edge turbulence analysis in QUEST

A fast visible imaging system is installed on the spherical tokamak QUEST to study edge turbulence. The camera uses a complementary metal-oxide semiconductor detector with a maximum resolution of 1024 × 1024 at 7000 frames∕s (fps) and can achieve 775 kfps at a resolution of 128 × 24. In this paper, we present the salient features of the system and its application to study edge turbulence in 8.2 GHz ECRH driven slab plasma, without plasma current. Vertical magnetic field (B(z)) topology is varied with three sets of poloidal field (PF) coils and the variation in the edge turbulence is investigated as a function of the B(z) strength and curvature. Fluctuation amplitude was highest for the shallow PF well. Cross-correlation coefficient shows distinct coherent mode along z direction at the steep density gradient region and it grows with the PF mirror ratio.

Pedestal Structure Model

Predictions are developed for gradients and profiles of the electron density and temperature in tokamak H-mode pedestals that are in transport quasiequilibrium. They are based on assuming paleoclassical processes provide the irreducible minimum radial plasma transport and dominate in the steep gradient regions of pedestals. The predictions agree (within a factor of about two) with properties of a number of pedestal experimental results.

The effect of progressively increasing lithium coatings on plasma discharge characteristics, transport, edge profiles and ELM stability in the National Spherical Torus Experiment

Lithium wall coatings have been shown to reduce recycling, suppress edge-localized modes (ELMs), and improve energy confinement in the National Spherical Torus Experiment (NSTX). Here we document the effect of gradually increasing lithium wall coatings on the discharge characteristics, with the reference ELMy discharges obtained in boronized, i.e. non-lithiated conditions. We observed a continuous but not quite monotonic reduction in recycling and improvement in energy confinement, a gradual alteration of edge plasma profiles, and slowly increasing periods of ELM quiescence. The measured edge plasma profiles during the lithium-coating scan were simulated with the SOLPS code, which quantified the reduction in divertor recycling coefficient from ∼98% to ∼90%. The reduction in recycling and fuelling, coupled with a drop in the edge particle transport rate, reduced the average edge density profile gradient, and shifted it radially inwards from the separatrix location. In contrast, the edge electron temperature (Te) profile was unaffected in the H-mode pedestal steep gradient region within the last 5% of normalized poloidal flux, ψN ; however, the Te gradient became steeper at the top of the H-mode pedestal for 0.8 < ψN < 0.94 with lithium coatings. The peak pressure gradients were comparable during ELMy and ELM-free phases, but were shifted away from the separatrix in the ELM-free discharges, which is stabilizing to the current-driven instabilities thought to be responsible for ELMs in NSTX.

SU‐E‐T‐372: Optimal Selection of Plane and Alignment Based on Quantitative Evaluation Using Three‐Dimensional (3D) Dose Data for IMRT and VMAT Dosimetry

Purpose: Gamma, DTA and dose difference (DD) evaluations could take into account only the two axes on the evaluation plane for IMRT and VMAT plan verification dosimetry. However, some steep dose gradient region on another axis with the errors of measurement setup and the laser alignment can decrease the agreement between the calculation and measurement on the plane. In this study, we developed an optimal selection method of finding optimal plane of the evaluation and adequate alignment of the measurement data using three‐dimensional dose data. Methods: After the isocenter alignment of the measurement data manually, the optimal selection engine reconstructs dose planes at certain locations on the axis perpendicular to the evaluation plane from the 3D data of dose calculation. then, the calculation planes are compared with the measurement plane using gamma evaluation in order to choose the candidates of the best plane of the evaluation. Using the candidates with the combinations with rotations and shifts, DD evaluation is conducted to find out the best plane and the best combination of shift and rotation. To assess the effectiveness of the method, a head and neck IMRT plan measurement was performed and the path ratios of gamma evaluation (3%/3mm criteria) were measured with optimal selection and non‐optimal selection method, respectively. Results: Average pass ratio of gamma evaluation with the optimal selection method was14.2%‐better than with the non‐optimal selection method. Additionally, the method found 0.5mm‐ and 1.5mm‐deviations in the two‐axis on the evaluation plane, respectively. 1.0mm‐deviation was also measured on the axis perpendicular to the plane. Conclusions: IMRT and VMAT verification measurement with the method could provide us not only the dosimetric check of the plan with better result but also the mechanical test of isocenter laser alignment.

SU-E-T-80: Development of IMRT Postal Audit Phantom Using Radiophotoluminescence Glass Dosimeter

Purpose: The purpose of this study is to develop IMRT postal audit phantom using radiophotoluminescence glass dosimeter, and to report initial experiences of the phantom. Method and Materials:We developed the IMRT postal audit phantom. The phantom can be inserted with both RPL glass dosimeter, GD‐302M (Asahi Techno Glass) for point dose verification and Radiochromic film, EBT2 (ISP) for relative planar dose verification. In the dedicated phantom, RPL glass dosimeter can be placed in 4 positions corresponding to target and 1 position to OAR. The EBT2 film can be inserted on the central transverse plane in the phantom. The phantom was made of water substitute material, Tough Water WE‐211 (Kyoto kagaku). for the initial experiences, 7 fields segmental MLCIMRT was planned with XiO (Elekta) using 6 & 10 MV from Clinac iX‐S. In addition, to evaluate the measurement accuracy of RPL glass dosimeter, point doses with ionization chamber (PTW 30013 Farmer type and PTW 31016 Pinpoint 3D) were measured under the same conditions. Results: Differences between the point dose with RPL glass dosimeter and that with Pinpoint 3D chamber agreed within 2% at all positions (high and low dose regions). Point dose differences between with Farmer chamber and with Pinpoint 3D chamber agreed within 1% at target (high dose region). At OAR (low dose and steep dose gradient region), however, the dose difference was exceeded by 5%. This is due to volume averaging effect of Farmer chamber.Conclusion: Feasibility study of IMRT postal audit phantom was performed. The measurement dose with RPL glass dosimeter was good agreement with Pinpoint 3D ionization chamber. Therefore, the dedicated phantom using RPL glass dosimeter shows considerable potential for the IMRT postal audit. To establish IMRT postal audit in Japan, we are starting dummy run now.