Measurements of multiple heat flux components at the divertor target by using surface eroding thermocouples (invited)

The Surface Eroding Thermocouple (SETC) is a robust diagnostic utilized in DIII-D to provide fast, edge-localized modes (ELMs) resolved heat flux measurements, in particular in geometric regions that are too shadowed for traditional infrared thermography. In order to further investigate the power dissipation in the divertor region, a combination of flush-mounted and recessed SETCs was developed to assess the effect on surface heating from non-charged particles at the divertor target. Utilizing the Divertor Materials Evaluation System sample exposure platform, the first demonstration of the feasibility of using this new method to distinguish between the heat flux from charged particles and that from neutrals and radiative heating was achieved. This paper details the process of using the combination of flush SETCs and recessed SETCs to measure the multiple heat flux components at the divertor target and further discusses how to determine two important ratios, α (ratio of heat flux from charged particles deposit on recessed SETC to that deposit on flush SETC) and β (ratio of heat flux from non-charged particles deposit on recessed SETC to that deposit on flush SETC), in the estimation of the heat flux from non-charged particle sources. Using a time dependent ratio α, it was found that ∼50% of the total incident heat flux is attributable to the non-charged particles in the fully detached open divertor in DIII-D. Finally, the new application of similar SETC diagnostics in the Small Angle Slot divertor with a V-like configuration and partial tungsten coated surface (SAS-VW) is also introduced.

Langmuir probe array for the small angle slot divertor in DIII-D

The DIII-D small angle slot (SAS) divertor is designed for divertor physics studies with enhanced neutral confinement and special target geometries in a closed divertor. The closed nature of the SAS makes optical diagnostic measurements difficult, so a specially designed, multipurpose array of Langmuir probes has been implemented to study the plasma conditions in and around the slot. The probes are spaced to provide at least 2 mm resolution (shorter than the energy decay length) of the near scrape-off layer when mapped to the outer mid-plane. Due to space limitations at the bottom of the slot, a novel spring-loaded probe and tile design was developed to clamp several short rooftop probe tips and insulators to the cooled baseplate. Initial probe measurements revealed tile to tile edge shadowing, especially where magnetic field line surface angles were less than 1°. Additionally, it was found, using three Langmuir probes (at 90°, 180°, and 270°), that the strike point variation of ±5 mm radially around the torus was not well aligned with the circular slot geometry [Watkins et al., Nucl. Mater. Energy 18, 46 (2019)]. These issues were resolved by (1) designing tiles with all probes mounted near the tile center instead of near the edges and (2) aligning these new custom tiles to the measured strike point toroidal surface with a very accurate laser scanning alignment tool. Post-alignment Langmuir probe measurements and plasma behavior demonstrated close agreement at two separate toroidal locations that were 45° apart.

Integration of full divertor detachment with improved core confinement for tokamak fusion plasmas

Divertor detachment offers a promising solution to the challenge of plasma-wall interactions for steady-state operation of fusion reactors. Here, we demonstrate the excellent compatibility of actively controlled full divertor detachment with a high-performance (βN ~ 3, H98 ~ 1.5) core plasma, using high-βp (poloidal beta, βp > 2) scenario characterized by a sustained core internal transport barrier (ITB) and a modest edge transport barrier (ETB) in DIII-D tokamak. The high-βp high-confinement scenario facilitates divertor detachment which, in turn, promotes the development of an even stronger ITB at large radius with a weaker ETB. This self-organized synergy between ITB and ETB, leads to a net gain in energy confinement, in contrast to the net confinement loss caused by divertor detachment in standard H-modes. These results show the potential of integrating excellent core plasma performance with an efficient divertor solution, an essential step towards steady-state operation of reactor-grade plasmas.

First Evidence of Local E×B Drift in the Divertor Influencing the Structure and Stability of Confined Plasma near the Edge of Fusion Devices

The structure of the edge plasma in a magnetic confinement system has a strong impact on the overall plasma performance. We uncover for the first time a magnetic-field-direction dependent density shelf, i.e., local flattening of the density radial profile near the magnetic separatrix, in high confinement plasmas with low edge collisionality in the DIII-D tokamak. The density shelf is correlated with a doubly peaked density profile near the divertor target plate, which tends to occur for operation with the ion B×∇B drift direction away from the X-point, as currently employed for DIII-D advanced tokamak scenarios. This double-peaked divertor plasma profile is connected via the E×B drifts, arising from a strong radial electric field induced by the radial electron temperature gradient near the divertor target. The drifts lead to the reversal of the poloidal flow above the divertor target, resulting in the formation of the density shelf. The edge density shelf can be further enhanced at higher heating power, preventing large, periodic bursts of the plasma, i.e., edge-localized modes, in the edge region, consistent with ideal magnetohydrodynamics calculations.

Imaging divertor strike point splitting in RMP ELM suppression experiments in the DIII-D tokamak

Fast visible imaging of the lower divertor from above is used to study the structure and dynamics of lobes induced by resonant magnetic perturbations (RMPs) in Edge-Localized Mode (ELM) suppression experiments in DIII-D. The best compromise between the amount of light and sharp imaging was obtained using emission at 601 nm from Fulcher band molecular deuterium. Multiple spatially resolved peaks in the D₂ emission, taken as a proxy for the particle flux, are readily resolved during RMPs, in contrast to the heat flux measured by infrared cameras, which shows little spatial structure in ITER-like conditions. The 25 mm objective lens provides high spatial resolution (2-4 mm/pixel) from the centerpost to the outer shelf over 40° toroidally that overlaps the field of view of the IRTV that measures the divertor heat flux, allowing direct comparison in non-axisymmetric discharges. The image is coupled to a Phantom 7.3 camera using a Schott wound fiber bundle, providing high temporal resolution that allows the lobe dynamics to be resolved between ELMs and across ELM suppression onset. These measurements are used to study the heat and particle flux in 3D magnetic fields and to validate models for the plasma response to RMPs.

Embedded calibration system for the DIII-D Langmuir probe analog fiber optic links

This paper describes a generally applicable technique for simultaneously measuring offset and gain of 64 analog fiber optic data links used for the DIII-D fixed Langmuir probes by embedding a reference voltage waveform in the optical transmitted signal before every tokamak shot. The calibrated data channels allow calibration of the power supply control fiber optic links as well. The array of fiber optic links and the embedded calibration system described here makes possible the use of superior modern data acquisition electronics in the control room.

High heat flux Langmuir probe array for the DIII-D divertor plates

Two modular arrays of Langmuir probes designed to handle a heat flux of up to 25 MW/m(2) for 10 s exposures have been installed in the lower divertor target plates of the DIII-D tokamak. The 20 pyrolytic graphite probe tips have more than three times higher thermal conductivity and 16 times larger mass than the original DIII-D isotropic graphite probes. The probe tips have a fixed 12.5 degree surface angle to distribute the heat flux more uniformly than the previous 6 mm diameter domed collectors and a symmetric "rooftop" design to allow operation with reversed toroidal magnetic field. A large spring-loaded contact area improves heat conduction from each probe tip through a ceramic insulator into a cooled graphite divertor floor tile. The probe tips, brazed to molybdenum foil to ensure good electrical contact, are mounted in a ceramic tray for electrical isolation and reliable cable connections. The new probes are located 1.5 cm radially apart in a staggered arrangement near the entrance to the lower divertor pumping baffle and are linearly spaced 3 cm apart on the shelf above the in-vessel cryopump. Typical target plate profiles of J(sat), T(e), and V(f) with 4 mm spatial resolution are shown.

Suppression of large edge-localized modes in high-confinement DIII-D plasmas with a stochastic magnetic boundary

A stochastic magnetic boundary, produced by an applied edge resonant magnetic perturbation, is used to suppress most large edge-localized modes (ELMs) in high confinement (H-mode) plasmas. The resulting H mode displays rapid, small oscillations with a bursty character modulated by a coherent 130 Hz envelope. The H mode transport barrier and core confinement are unaffected by the stochastic boundary, despite a threefold drop in the toroidal rotation. These results demonstrate that stochastic boundaries are compatible with H modes and may be attractive for ELM control in next-step fusion tokamaks.

The psychodynamic treatment of combat neuroses (PTSD) with hypnosis during World War II

In a large Army hospital during World War II, a full-time program in hypnotherapy for battle trauma cases was developed. Symptoms included severe anxiety, phobias, conversions, hysterias, and dissociations. Many hypnoanalytic techniques were used, especially including abreactions. Good therapeutic results were frequent, as demonstrated by typical cases. There was no evidence that the abreactive procedure tended to retraumatize patients or initiate psychotic reactions.

Training in clinical hypnosis, a historical perspective: the Montana experience

When Dr. D. Corydon Hammond invited me to write a paper for this symposium on hypnosis training, it was obvious that its greatest contribution could be a description of the rather intensive program developed over 2 decades at the University of Montana. However, it became apparent that the Montana program was only part of some 50 years experience developing professional education in hypnosis, psychotherapy, and graduate training in general. At the risk of being accused of immodesty I must therefore write much of this contribution in the first person.

Organization and functioning of ISCEH, The International Society for Clinical and Experimental Hypnosis

The first international society of hypnosis founded in this century, the International Society for Clinical and Experimental Hypnosis (ISCEH), was organized in 1958 as a direct result of societal conflicts between The Society for Clinical and Experimental Hypnosis (SCEH) and the American Society of Clinical Hypnosis (ASCH). Initially, it consisted of National Divisions built around key contributors in 30 different countries. This article describes the inception, organization, and development (including controversies and conflicts) of ISCEH up to 1973. At that time, through the cooperation of SCEH, ASCH, and other international groups, under the leadership of Dr. Ernest R Hilgard, ISCEH was reorganized, reconstituted, and renamed The International Society of Hypnosis (ISH). For the purpose of historical study, the society's voluminous correspondence, directories of officers and committees, awards, photographs, programs of congresses, election records, and other relevant documents have been cataloged and preserved in some 82 files in the Archives of the History of American Psychology at the University of Akron, Akron, Ohio.

Public health nursing research priorities: a collaborative Delphi study

The purpose of this study was to identify research questions and priorities in public health nursing based on the perceived needs of practicing public health nurses, and to assess whether the respondents believed that the profession should provide leadership in the study of the identified questions. Using a modified Delphi survey, 76 research priorities were ranked and produced three factors or categories of questions during the two rounds: outcomes in maternal-child and family planning, outcomes in home health services, and public health nurse recruitment, retention, job satisfaction, and image. Forty-seven (62%) of the 76 priorities were deemed appropriate for nursing to assume leadership in seeking answers. Results reveal a consensus of research priorities generated by front-line nurses consistent with year 2000 health objectives for the nation.

Accessing the relevant areas of maladaptive personality functioning

Personality functions in different dimensions: perceptual, cognitive, and affective (emotional). It can be manifested in different areas--overt (conscious), covert (unconscious), or in some relative degree of each. Personality segments can operate independently of one another, as in multiple personalities or with varying degrees of mutual dependence and intercommunication, as in normal "ego states." Therapeutic interventions will be more efficient if focused within the problem dimension, area, or segment. The essence of Alexander and French's "corrective emotional experience" was a restructuring of the patient through release and interpretation within the "emotional" sphere. When their concept is extended to other dimensions of personality functions, such as behavioral, perceptual, and cognitive, it allows interventions to be more specifically focused in the regions that are most relevant. In this paper we present specific techniques using this extended concept. Rapid and significant change followed in the patient so treated.

Dissociation and displacement: where goes the "ouch?"

Hypnosis is widely used to relieve pain. Current theory emphasizes its dissociative features. Multiple personality patients can eliminate pain in the primary personality by displacing it into underlying alters. The Hilgards demonstrated that normal hypnotized subjects can similarly dissociate pain into a covert cognitive structural system which they called the "hidden observer." The Watkins discovered that "hidden observers" appeared to be the same phenomenon as "ego states." "Ego-state theory" assumes that human personality develops through integration and differentiation. At one end of the continuum, "differentiation" is adaptive. Ego states possess relatively permeable boundaries as in normal moods. At the other end ego-state boundaries become less permeable. Normal "differentiation" becomes maladaptive "dissociation" and multiple personalities may be created. In the intermediate range of the differentiation/dissociation continuum, "covert" ego states can be found in many normal subjects who volunteer for hypnotic laboratory experiments. Normal individuals, like multiple personalities and "hidden observer" subjects, can displace (dissociate) pain into "covert" ego states. The pain is not eliminated. This suggests that when we remove pain by hypnosis we may not be getting away "scot-free."

Hazards to the therapist in the treatment of multiple personalities

It is vitally important that the therapist be cognizant of the dangers inherent in treating some patients with multiple personality disorder. The authors offer sound, detailed advice on every facet of the clinician's interaction with the patient--from keeping on good terms with each ego state to guarding against physical violence and sexual seduction.

[Methods and relationships in hypnotism]

Hypnotism is as much an intensive and intrapersonal relationship as a state of awareness. It is therefore necessary to know how to induce this state, so that the therapeutist can achieve the best results. Ways in which this can be done are described and particular hypnotherapeutic methods that enable the technique to be managed with success are explained. Special attention is given to the concepts of relationship and suggestion. Purification and verbal catharsis under hypnosis are described, along with abreaction as a therapeutic instrument. Cases of free and selective association are presented, together with others illustrating strategic techniques for manipulation between subject and object. Personal methods are defined in the sense of suitable mechanisms enabling the hypnotist to establish what can be seen as a true state of equilibrium between himself and his patient.

[Methods and relationships in hypotism]

Hypotism is as much an intensive and intrapersonal relationship as a state of awareness. It is therefore necessary to know how to induce this state, so that the therapeutist can achieve the best results. Ways in which this can be done are described and particular hypotherapeutic methods that enable the technique to be managed with success are explained. Special attention is given to the concepts of relationship and suggestion. Purification and verbal catharasis under hyponosis are described, along with abreaction as a therapeutic instrument. Cases of free and selective association are presented, together with others illustrating strategic techniques for manipulation beteen subject and object. Personal methods are defined in the sense of suitable mechanisms enabling the hypnotist to establish hat can be seen as a true state of equilibrium beteen himself and his patient.