High Pedestal Research Articles

High resolution density pedestal measurements during edge localized modes by short-pulse reflectometry in the TCV tokamak

This publication presents high spatio-temporal resolution (mm µs−1) density profile measurements of the pedestal top during type I, III, and small edge localized mode (ELM) H-mode plasmas in the tokamak à configuration variable (TCV). These measurements were performed using a novel short-pulse reflectometer. Average inter-ELM density profiles are obtained via conditional averaging using the D trace as ELM indicator. Changes to the pedestal density profile gradients prior to type-III ELMs reveal unique pedestal dynamics leading to the ELM crash which can provide important experimental data for validation of non-linear MHD ELM simulations. The small-ELM scenario is found to feature a ∼25–35 kHz quasi-coherent density fluctuation near the separatrix 0.993–1.05 not observed during a similar type-I ELM discharge. This oscillation is also found in low-field-side magnetic pick-up probes displaying a ballooning character and n = +1 toroidal mode number. This oscillation could help explain the markedly different pedestal dynamics observed in the small-ELM regime.

An approach for simulating the interaction between soil and discontinuous structure with mixed interpolation interface

Structural discontinuities are common (e.g. cracks, segmented structures) especially in large-scale geotechnical structures, which can lead to the discontinuous soil-structure interaction (SSI) problems. Thus, in this paper a mixed interpolation interface with non-matching nodes is introduced for effectively simulating discontinuous SSI problems. This paper provides a conveniently executed numerical implementation of the introduced approach within a finite element method (FEM) analysis platform. The high flexibility and precision of the developed method are demonstrated through fine analyses of 2D and 3D concrete faced rockfill dams (CFRDs). Furthermore, a cracking evolution analysis for a high pedestal of the Quxue asphalt concrete core dam is conducted by coupling the method with a cohesive zone model (CZM). The mixed interpolation interface is verified as an effective tool for solving discontinuous SSI problems. The modeling also sheds light on the process of cracking evolution and the primary failure mechanism for high pedestal.

The role of edge fueling in determining the pedestal density in high neutral opacity Alcator C-Mod experiments

SOLPS-ITER modeling of EDA H-mode experiments on Alcator C-Mod find that the electron density pedestal structure is unaffected by increased gas fueling when approaching ITER-like opaqueness conditions. SOLPS-ITER simulations show a decrease in the neutral penetration depth with increasing pedestal density, similar to prior experiments (Hughes et al., 2006). Neutral density and penetration depth vary poloidally, and we show that the highest neutral densities at the separatrix are found closest to the gas puff locations both on the high field side and the low field side. The decrease in the neutral penetration depth with increasing pedestal density, as well as the decrease in the neutral density at the separatrix, are not just limited to the midplane, but persist at every poloidal location. We find, however, that when gas puffs of similar magnitude as those employed in experiments are added, a much larger increase in the electron density is observed over the whole modeled plasma radius. This does suggest that changes in transport will need to be included self-consistently. • SOLPS-ITER provides insight on the dynamics of neutrals in high opacity H-modes. • SOL neutral opacity can be quantified by radial neutral density e-folding length. • Density pedestal formation is mostly unaffected as pedestal opacity increases. increases. • High gas-puffing only moderately increases neutral penetration of the pedestal. • At high pedestal opacity, main chamber fueling dominates fueling through the X-point.

On the stability and stationarity of the Super H-mode combined with an ion transport barrier in the core

The Super H-mode, a regime with high pedestal pressure and stored energy, is explored on DIII-D and combined with an ion transport barrier in the plasma core to increase performance. A significant improvement of ion temperatures and confinement is facilitated by favorable conditions such as high rotational shear and high ion pedestal temperatures. As a result of a rise in density and simultaneous decrease in rotation, the ion transport barrier disappears during the discharge evolution, leading to a transition from a very high confinement state at early times, to a reduced but still high confinement phase. Additionally, in many discharges, a global magnetohydrodynamic (MHD) event consistent with the coupling of a destabilized internal mode to an edge localized mode causes a large energy loss and leads to a reorganization of the plasma into a lower temperature, higher density state. Depending on the magnitude of the global MHD event, the plasma edge collisionality can increase significantly and shift the operational boundary from the peeling to the ballooning side, which can be understood as a drop out of the Super H-mode channel into standard H-mode. Hence, in Super H-mode discharges with ion transport barriers, both the improved pedestal height and rotational shear contribute to the high stored energy. At very low levels of rotation, the confinement factor for SH modes is still expected to exceed standard H-mode by 20%–30%. With their overall stationarity and high-performance levels, Super H-mode discharges provide an attractive regime for ITER and may enable a more compact design of future fusion power plants.

Reduction of Phase-Modulation to Intensity-Modulation Conversion Noise Effect Using Delayed Self-Homodyne Optical Orthogonal Frequency Division Multiplexing System

Self-homodyne optical orthogonal frequency division multiplexing (OFDM) transmission system is a variant of self-coherent systems with a relaxed laser linewidth requirement as opposed to a full coherent system. The system is designed by transmitting a carrier together with the subcarriers, ensuring a strong phase-correlation between them at a receiver compared to the coherent system where only the subcarriers are transmitted. Despite the strong phase-correlation, the laser phase noise (PN) can still degrade the self-homodyne system performance due to the interaction of the PN with a chromatic dispersion (CD) induces a phase-modulation to intensity-modulation (PM-to-IM) conversion noise which cannot be canceled using a balanced-receiver. This imposes a high noise pedestal underneath each subcarrier, with the highest pedestal's peak imposed beneath the subcarriers that are farthest away from the carrier. This in turn produces a phase-decorrelation between the carrier and subcarriers which degrades the Q-factor between the lowest and highest subcarrier frequencies. In this work, the effect of the PM-to-IM conversion noise is reduced for the transmission of up to 174 Gb/s using a simple delay-line assigned to realign the phase-decorrelation of the subcarriers. With this technique, the subcarriers Q-degradation can be improved and the total transmission length can be tripled with Q-improvements of 5.4, 5.3, and 5-dB for 16-quadrature amplitude modulation (QAM) over 1360 km, 32- QAM over 800 km, and 64-QAM over 480 km, respectively, using 10-MHz LW with a 15-GHz total signal bandwidth. For 29 GHz signal bandwidth, the phase-walk-off of the high frequency subcarrier becomes more severe where the introduced delay can increase the transmission length by 2.5 times than without the delay, which increased the signal tolerance to the conversion noise.

Projections of H-mode access and edge pedestal in the SPARC tokamak

In order to inform core performance projections and divertor design, the baseline SPARC tokamak plasma discharge is evaluated for its expected H-mode access, pedestal pressure and edge-localized mode (ELM) characteristics. A clear window for H-mode access is predicted for full field DT plasmas, with the available 25 MW of design auxiliary power. Additional alpha heating is likely needed for H-mode sustainment. Pressure pedestal predictions in the developed H-mode are surveyed using the EPED model. The projected SPARC pedestal would be limited dominantly by peeling modes and may achieve pressures in excess of 0.3 MPa at a density of approximately 3 × 1020m−3. High pedestal pressure is partially enabled by strong equilibrium shaping, which has been increased as part of recent design iterations. Edge-localized modes (ELMs) with >1 MJ of energy are projected, and approaches for reducing the ELM size, and thus the peak energy fluence to divertor surfaces, are under consideration. The high pedestal predicted for SPARC provides ample margin to satisfy its high fusion gain (Q) mission, so that even if ELM mitigation techniques result in a 2× reduction of the pedestal pressure,Q> 2 is still predicted.

Effects of triangularity on the fusion performance of CFETR

An important task of the China Fusion Engineering Test Reactor physics design is to develop operation scenarios with high fusion power (1 GW), high bootstrap current fraction for steady-state and a plasma edge compatible with heat and particle exhaust. To achieve these goals, triangularity (δ) effects on the fusion performance of two candidate scenarios, with or without reversed magnetic shear (RS), namely conventional H-mode and RS H-mode, are evaluated using core-edge coupled integrated modeling in this paper. For fixed pedestal density, it is shown that higher δ is favorable for higher fusion performance in the conventional H-mode scenario while the fusion performance decreases with increasing δ in the RS H-mode scenario. In conventional H-mode, the higher fusion performance at high δ mainly comes from a higher pedestal temperature as predicted by EPED in combination with stiff core kinetic profiles. In the RS H-mode scenario with a local reversed shear region, the profiles are non-stiff and a strong internal transport barrier (ITB) exists at low δ. This results in higher density and temperature inside the ITB for low δ, leading to higher fusion power. If the pedestal temperature is kept fixed, in both scenarios the significant increase in pedestal density, which extends into the core, dominates at high δ and leads to much higher fusion power. For conventional H-mode, destabilization from increasing δ is partially balanced by stabilization due to increasing ν*. Since the normalized heat sources are quite similar, it results in minimal changes in the temperature profiles except for the lowest density case. For RS H-mode, destabilization from increasing δ is approximately balanced by stabilization due to increasing ν* in foot region, but a strong temperature ITB is still evident for low δ. The ability to take advantage of the high pedestal density in conventional H-mode and reversed shear scenario depends on its compatibility with edge density requirements from efficient heat and particle exhaust. Transport analysis is presented to elucidate the roles of δ, collisionality and magnetic shear in altering the profiles and the ITB, which contribute to the different behavior in the two scenarios.

MOKONE V ATTORNEY-GENERAL AND OTHERS (2018): MANIFESTATION OF EXECUTIVE-MINDED JUDICIARY IN BOTSWANA

This is a theoretical paper that seeks to shine the light on the concept of executive-minded judiciary in Botswana. In order to delve deeper into the meaning of the word, the paper traces its origin by reference to other jurisdictions. The paper argues that executive-mindedness is inimical to independence of the judiciary. It is argued that independence of the judiciary stands at the heart of a democracy like Botswana. Judges must not only demonstrate independence but also that they are accountable to the public. The paper does not claim that the judiciary in Botswana is not independent or irresponsible. To the contrary, Botswana is respected globally for its commitment to the rule of law and independence of the judiciary, which is constitutionally entrenched. Rather, the argument is that Botswana must not only retain its record but must step up efforts to improve this and be vigilant at all times to retain integrity of the judiciary. A country like South Korea, with a fiercely independent judiciary, especially its Constitutional Court, is a model to benchmark on. To further enhance integrity in the Botswana judiciary, as the Law Society of Botswana and other parties have requested, action is needed to remove the secrecy that clouds the appointment of judges at both the High court and the Court of Appeal. Transparency is needed in the recruitment and appointment of judges. Public hearings and or publications of portions of deliberations of the Judicial Service Commission would help achieve this openness. As the Court of Appeal has washed its hands on this matter, it is the executive branch that must move for the amendment of the constitution to achieve this. Alternatively a private member’s bill should be tabled. That will put Botswana’s democracy on a higher pedestal. The paper uses the case Mokone v Attorney-General and others (2018) to illustrate the manifestation of executive-mindedness. It argues that remarks uttered in the obiter by Justice Brand not only showed a leaning towards the executive but also have a potential chilling effect on press freedom. The press in this matter had not behaved responsibly, it is admitted, but the judge went overboard as well.

Transport at high and development of candidate steady state scenarios for ITER

On DIII-D, the high scenario has an internal transport barrier (ITB), , , and very high normalized confinement . Recently, plasmas starting with these conditions have been dynamically driven to and , where we find the ITB and high performance persist for five energy confinement times. These conditions are projected to meet the ITER steady-state goal of Q = 5. The ITB is maintained at lower with a strong reverse shear, consistent with predictions that negative central shear can lower the threshold for the ITB. There are two observed confinement states in the high scenario: H-mode confinement state with a high edge pedestal, and an enhanced confinement state with a low pedestal and an ITB. It has been observed in a scan of external resonant magnetic perturbation amplitude that when there are no large type-I ELMs, there is no transition to enhanced confinement. This is consistent with the proposed mechanism for ITB formation being a type-I ELM. Quasilinear gyro-Landau fluid predictive modeling of ITER suggests that only a modest reverse shear is required to achieve the ITB formation necessary for Q = 5 when electromagnetic physics including the kinetic ballooning mode (KBM) is incorporated.

KSTAR Status and Upgrade Plan Toward Fusion Reactor

Korea Superconducting Tokamak Advanced Research (KSTAR) program has made significant advances in the development of long pulse and high-performance plasma scenarios, utilizing the advantages of the fully superconducting tokamak. Ten years of KSTAR operation have produced outstanding progress in plasma control, extending the operating window of the plasma discharges, and achieving the H-mode up to 1.2 MA in plasma current, up to 90 s at top duration, and up to 2.16 in elongation. The unique features of the KSTAR device also produced a record 30 s long pulse in H-mode operation without an edge-localized-mode (ELM) crash, and progress in the fundamental transport physics through systematic study, using unique diagnostic capabilities. Therefore, the next near-term research focus will be on how to extend the high performance plasmas up to 300 s by overcoming scientific and engineering obstacles to steady state operation. For fusion reactors, the tokamak device needs to sustain a permanent plasma current. It is also known that the bootstrap current should play an important role in the plasma current for an efficient fusion reactor, and its contribution should be over as high as possible. An internal transport barrier discharge based on the reverse shear profile of the safety factor is one of the promising candidates for enhancing the bootstrap current. However, even in reverse shear mode, an additional external off axis current drive (CD) should be provided to control the current profile, as well as to supplement the plasma current. KSTAR has pursued steady state to operation, aiming for a fully non inductive state, based on real time (RT) plasma control by maximizing the long pulse capabilities of the superconducting machine. In order to deposit current at an arbitrary position, the first requirement is to have many highly efficient CD actuators capable of profile diversity. KSTAR has prepared several RF CD portfolios in addition to a conventional on and off axis CD neutral beam injection (NBI) system. The final target of an off axis current drive will be a 4 MW off-axis NB, 8 MW on-axis NB, 6 MW electron cyclotron heating (ECH), and 4 MW radio frequency heating and current drive (RFHCD) (ion cyclotron (IC), lower hybrid (LH), Helicon CD). In addition, as a long-term goal, demonstrating a long pulse core edge compatible plasma in a reactor relevant condition is important in present medium size tokamak, since it is expected to sustain a very high pressure pedestal height plasma using super H-mode, with parallel upgrades of the superconducting toroidal field (TF) coils.

On the very high energy confinement observed in super H-mode DIII-D experiments

Analysis of recent super H-mode experiments on DIII-D shows that high rotation, not high pedestal, plays the essential role in achieving very high confinement . Very high confinement is reached early on in the H-mode phase of these discharges, when the pedestal is still very low, but after the toroidal rotation has already built-up to very high levels in the core. As the discharge evolves, the rotation drops, and so does the energy confinement, despite a sustained very high pressure pedestal. During this evolution, the confinement quality is linearly correlated with the core toroidal rotation, which varies according to different levels of injected neutral beam torque per particle. Core transport modeling shows that the contribution from rotation in the shear is responsible for confinement quality significantly in excess of standard H-mode ().

Experimental observation of coexisting electromagnetic fluctuations correlating with the inter-ELM pedestal evolution on EAST

Correlations between the edge fluctuations and the pedestal evolution during the relatively large edge localized mode (ELM) cycles at high pedestal normalized electron collisionality (νe,ped* > 1) on the EAST tokamak are investigated. Not only the edge electrostatic coherent mode (ECM, ∼50 kHz) and the low frequency magnetic coherent mode (MCM, ∼32 kHz) but also a high frequency electromagnetic mode (HFM, >150 kHz) are observed to be coexisting between ELMs. After the ELM crash, the pedestal electron temperature recovered faster than the pedestal electron density. It is found that the saturation of the ECM coincides more with the saturation of the pedestal electron density, while the saturation of the HFM and MCM coincides more with the saturation of the pedestal electron temperature. In addition, the characteristics of the electromagnetic fluctuations (the HFM and MCM) are studied in detail: the HFM propagates in the electron diamagnetic drift direction in the laboratory frame with an average poloidal wave number of k¯θHFM≈0.17 cm−1, while the MCM propagates in the ion diamagnetic drift direction in the laboratory frame with k¯θMCM ≈ 0.12 cm−1 and the toroidal mode number of n = 1. Furthermore, both the HFM and MCM have inward average radial wave numbers of k¯RHFM≈0.13 cm−1 and k¯RMCM≈4.64 cm−1. The bispectral analysis shows that the HFM and MCM have strong nonlinear interactions. The HFM is clearly observed on both low and high field side Mirnov coils, which might suggest a feature beyond a ballooning type instability, e.g., the kinetic ballooning mode. These studies may contribute to a better understanding of the pedestal evolution.

The New Myth of Beethoven

Noli has been reluctant to, as a historical creator, to deal more with heroes and bring them down from their high and untouchable pedestal in midst of to common people, where they will live, rejoice and suffer, conquer and fail with them. In addition, his opinion is inspired by firm belief that the real man is more interesting than all legendary heroes brought together, for simple reason that latter are a product of hero’s imagination. However, Noli demystifies myths, for though he sees Beethoven from every possible human lacquer and strips him of elements that make him divine, he will create new myth, one of Beethoven human. Therefore, from anti-myth we come to myth, now to new myth. It seems to Noli that this reckless glorification of hero, which has nothing to do with truth, is prevented. With power of arguments, he causes hero to descend from legendary heights on earth. He cuts off wings of idolatry and gives it real dimensions. Therefore, overthrown myth of Beethoven's aristocrat is brought back into play as a humanized myth.

Shafranov shift bifurcation of turbulent transport in the high βp scenario on DIII-D

Shafranov shift stabilization of turbulence creates a bifurcation in transport, leading to multiple confinement states in the high βp scenario on DIII-D: an H-mode confinement state with a high edge pedestal, and an enhanced confinement state with a low pedestal and an internal transport barrier (ITB). The bifurcation is observed experimentally in the ion energy transport with respect to mid-radius (ρ = 0.6) pressure gradient. Simultaneously, the electron transport exhibits a similar but less dramatic behavior with respect to pressure gradient. The Shafranov shift is found to increase at the same time as the transition to enhanced confinement, and quasilinear gyro-Landau fluid modeling shows a reduction of predicted energy flux consistent on-set of the ITB. Transient perturbations such as ELMs are likely a trigger for the transition between states by lowering the edge pressure and increasing mid-radius pressure gradient.

Formation of a High Pressure Staircase Pedestal with Suppressed Edge Localized Modes in the DIII-D Tokamak.

We observe the formation of a high-pressure staircase pedestal (≈16-20 kPa) in the DIII-D tokamak when large amplitude edge localized modes are suppressed using resonant magnetic perturbations. The staircase pedestal is characterized by a flattening of the density and temperature profiles in midpedestal creating a two-step staircase pedestal structure correlated with the appearance of midpedestal broadband fluctuations. The pedestal oscillates between the staircase and single-step structure every 40-60ms, correlated with oscillations in the heat and particle flux to the divertor.Gyrokinetic analysis using the cgyro code shows that when the heat and particle flux to the divertor decreases, the pedestal broadens and the E×B shear at the midpedestal decreases, triggering a transport bifurcation from the kinetic ballooning mode (KBM) to trapped electron mode (TEM) limited transport that flattens the density and temperature profiles at midpedestal and results in the formation of the staircase pedestal. As the heat flux to the divertor increases, the pedestal narrows and the E×B shear at the midpedestal increases, triggering a back transition from TEM to KBM limited transport. The pedestal pressure increases during the staircase phase, indicating that enhanced midpedestal turbulence can be beneficial for confinement.

DIII-D research towards establishing the scientific basis for future fusion reactors

DIII-D research is addressing critical challenges in preparation for ITER and the next generation of fusion devices through focusing on plasma physics fundamentals that underpin key fusion goals, understanding the interaction of disparate core and boundary plasma physics, and developing integrated scenarios for achieving high performance fusion regimes. Fundamental investigations into fusion energy science find that anomalous dissipation of runaway electrons (RE) that arise following a disruption is likely due to interactions with RE-driven kinetic instabilities, some of which have been directly observed, opening a new avenue for RE energy dissipation using naturally excited waves. Dimensionless parameter scaling of intrinsic rotation and gyrokinetic simulations give a predicted ITER rotation profile with significant turbulence stabilization. Coherence imaging spectroscopy confirms near sonic flow throughout the divertor towards the target, which may account for the convection-dominated parallel heat flux. Core-boundary integration studies show that the small angle slot divertor achieves detachment at lower density and extends plasma cooling across the divertor target plate, which is essential for controlling heat flux and erosion. The Super H-mode regime has been extended to high plasma current (2.0 MA) and density to achieve very high pedestal pressures (~30 kPa) and stored energy (3.2 MJ) with H98y2 ≈ 1.6–2.4. In scenario work, the ITER baseline Q = 10 scenario with zero injected torque is found to have a fusion gain metric independent of current between q95 = 2.8–3.7, and a lower limit of pedestal rotation for RMP ELM suppression has been found. In the wide pedestal QH-mode regime that exhibits improved performance and no ELMs, the start-up counter torque has been eliminated so that the entire discharge uses ≈0 injected torque and the operating space is more ITER-relevant. Finally, the high- (⩽3.8) hybrid scenario has been extended to the high-density levels necessary for radiating divertor operation, achieving ~40% divertor heat flux reduction using either argon or neon with Ptot up to 15 MW.

Finite Larmor radius effects at the high confinement mode pedestal and the related force-free steady state

In this letter, we will first relate our previous calculations on the radial electric field at the high confinement H-mode pedestal to the actual magnetic fusion experimental measurements. We will then discuss the new pressure balance due to the E × B current, which is induced by the resulting radial electric field, and its impact on the gyrokinetic MHD equations as well as their conservation properties in the force-free steady state. The recent controversy on the H-mode physics will also be addressed.

Influence of Mathematical and Astronomical Developments in Medieval Kerala on Vāstuśāstra

The contribution in the field of mathematics is unparalleled. The concept of zero and the place value system is alone sufficed to place India in a high pedestal. Historians were generally under the impression that Indian supremacy in Mathematics came to an end with Bhaskaracharya (1114–1185) who is also known as Bhaskara II.Recent researches and publications of books like ‘Crest of the peacock’ written by George Gheverghese Joseph, has brought out the marvelous achievements of Southern India, especially Kerala region after the period of Bhaskaracharya which produced many results surpassing the Europeans in its indigenous style till the advent of Western Education system in early 19th Cent. This medieval contribution includes mathematical analysis and first steps in Calculus and many outstanding discoveries in astronomy. These contributions in Mathematics as well as in Astronomy are now grouped and studied under the title “Kerala School”. Accordingly, Sangamagrama Madhava (14th Cent.), doyen of Kerala School, is recognized as the ‘Father of infinitesimal Analysis’.In this paper the attempt is made to analyse the influence of Kerala School in the development of traditional building science and architecture. This branch of knowledge is generally categorized under the term ‘Vāstuśāstra’.`

High Speed and Low Pedestal Error Bootstrapped CMOS Sample and Hold Circuit

<p>A new high speed, low pedestal error bootstrapped CMOS sample and hold (S/H) circuit is proposed for high speed analog-to-digital converter (ADC). The proposed circuit is made up of CMOS transmission gate (TG) switch and two new bootstrap circuits for each transistor in TG switch. Both TG switch and bootstrap circuits are used to decrease channel charge injection and on-resistance input signal dependency. In result, distortion can be reduced. The decrease of channel charge injection input signal dependency also makes the minimizing of pedestal error by adjusting the width of NMOS and PMOS of TG switch possible. The performance of the proposed circuit was evaluated using HSPICE 0.18-m CMOS process. For 50 MHz sinusoidal 1 V peak-to-peak differential input signal with a 1 GHz sampling clock, the proposed circuit achieves 2.75 mV maximum pedestal error, 0.542 mW power consumption, 90.87 dB SNR, 73.50 SINAD which is equal to 11.92 bits ENOB, -73.58 dB THD, and 73.95 dB SFDR.</p>

Relating the near SOL transport with plasma properties of the confined edge region in ASDEX Upgrade

An analysis of ASDEX Upgrade plasma is performed to understand the near SOL transport and develop the predictive basis for the electron temperature gradient, All of the unseeded L- and H-mode attached and N seeded H-mode discharges studied are shown that the analyzed ASDEX Upgrade dataset is in the conduction-limited regime, i.e. the parallel transport in the near SOL is dominated by Spitzer–Harm conduction. By studying a H–L back transition, it is shown that the ‘bifurcation’ in the core plasma between H- and L-mode regimes also exists in the perpendicular transport in the near SOL region. Through power balance and the Spitzer–Harm condution, the SOL perpendicular transport can be derived as with For detached plasmas, the SOL upstream electron profile is found to be broader than an equivalent attached plasma under certain conditions. By comparing with global energy confinement, it is found that the discharges with broadened profiles also have degraded confinement, while those with unchanged profiles have similar confinement to attached plasma. The widening of the SOL is also found to coincide with the dropping of upstream temperature. Finally, comparisons of a N seeded H-mode with high pedestal top pressure and an I-mode plasma with an L-mode reference are both found to break the generally observed correlation between the Te SOL decay length and the pedestal top pressure. Thus, the relationship is shown to be non-causal and must instead be due to similar dependences on other plasma parameters. This means that higher global energy confinement is not necessarily imply larger heat flux in the divertor and motivates the search for regimes that optimize both. The implications of these results for SOL transport are discussed.