27 research outputs found
Heavy quarkonium: progress, puzzles, and opportunities
A golden age for heavy quarkonium physics dawned a decade ago, initiated by
the confluence of exciting advances in quantum chromodynamics (QCD) and an
explosion of related experimental activity. The early years of this period were
chronicled in the Quarkonium Working Group (QWG) CERN Yellow Report (YR) in
2004, which presented a comprehensive review of the status of the field at that
time and provided specific recommendations for further progress. However, the
broad spectrum of subsequent breakthroughs, surprises, and continuing puzzles
could only be partially anticipated. Since the release of the YR, the BESII
program concluded only to give birth to BESIII; the -factories and CLEO-c
flourished; quarkonium production and polarization measurements at HERA and the
Tevatron matured; and heavy-ion collisions at RHIC have opened a window on the
deconfinement regime. All these experiments leave legacies of quality,
precision, and unsolved mysteries for quarkonium physics, and therefore beg for
continuing investigations. The plethora of newly-found quarkonium-like states
unleashed a flood of theoretical investigations into new forms of matter such
as quark-gluon hybrids, mesonic molecules, and tetraquarks. Measurements of the
spectroscopy, decays, production, and in-medium behavior of c\bar{c}, b\bar{b},
and b\bar{c} bound states have been shown to validate some theoretical
approaches to QCD and highlight lack of quantitative success for others. The
intriguing details of quarkonium suppression in heavy-ion collisions that have
emerged from RHIC have elevated the importance of separating hot- and
cold-nuclear-matter effects in quark-gluon plasma studies. This review
systematically addresses all these matters and concludes by prioritizing
directions for ongoing and future efforts.Comment: 182 pages, 112 figures. Editors: N. Brambilla, S. Eidelman, B. K.
Heltsley, R. Vogt. Section Coordinators: G. T. Bodwin, E. Eichten, A. D.
Frawley, A. B. Meyer, R. E. Mitchell, V. Papadimitriou, P. Petreczky, A. A.
Petrov, P. Robbe, A. Vair
Molecular cloning of growth hormone-encoding cDNA of an Indian major carp, Labeo rohita, and its expression in Escherichia coli and zebrafish
10.1006/gcen.2001.7759General and Comparative Endocrinology1252236-247GCEN
Erratum to Molecular cloning of growth hormone-encoding cDNA of an Indian major carp, Labeo rohita, and its expression in Escherichia coli and zebrafish [Gen. Comp. Endocrinol. 125, (2002), 236-247]
10.1016/j.ygcen.2010.01.013General and Comparative Endocrinology1671180-GCEN
Experiments of continuously and stably flowing lithium limiter in EAST towards a solution for the power exhaust of future fusion devices
Liquid lithium (Li) can partly ameliorate lifetime and power-exhaust issues of plasma facing components (PFCs) by enabling a self-healing, self-replenishing surface with a reduced susceptibility to neutron damage in future fusion devices. To assess operational stability and heat-exhaust capability under tokamak exposure, two generations of continuously flowing liquid Li (FLiLi) limiters on the concept of a thin flowing Li film have been successfully designed and tested in high performance discharges in EAST. The design uses a circulating Li layer with a thickness of <0.1 mm and a flow rate ∼2 cm3s−1. In addition, the limiter employs a novel electro-magnetic pump to drive liquid Li flow from a collector at the bottom of the limiter into a distributor at its top. Free surface gravitational flow closes the loop for a continuously flowing liquid Li film on the wetted PFC. Here we summarize key FLiLi limiter development and experimental results in H-mode plasmas. Keywords: Limiter, Lithium, Plasma facing component, EAS
Injected mass deposition thresholds for lithium granule instigated triggering of edge localized modes on EAST
The ability of an injected lithium granule to promptly trigger an edge localized mode (ELM) has been established in multiple experiments. By horizontally injecting granules ranging in diameter from 200 microns to 1mm in diameter into the low field side of EAST H-mode discharges we have determined that granules with diameter > 600 microns are successful in triggering ELMs more than 95% of the time. It was also demonstrated that below 600 microns the triggering efficiency decreased roughly with granule size. Granules were radially injected from the outer midplane with velocities ~ 80 m/s into EAST upper single null discharges with an ITER like tungsten monoblock divertor. These granules were individually tracked throughout their injection cycle in order to determine their efficacy at triggering an ELM. For those granules of sufficient size, ELM triggering was a prompt response to granule injection. By simulating the granule injection with an experimentally benchmarked neutral gas shielding (NGS) model, the ablatant mass deposition required to promptly trigger an ELM is calculated and the fractional mass deposition is determined.readme, digital data file
ELM elimination with Li powder injection in EAST discharges using the tungsten upper divertor
We report the first successful use of lithium (Li) to eliminate edge-localized modes (ELMs) with tungsten divertor plasma-facing components in the EAST device. Li powder injected into the scrape-off layer of the tungsten upper divertor successfully eliminated ELMs for 3-5 sec in EAST. The ELM elimination became progressively more effective in consecutive discharges at constant lithium delivery rates, and the divertor D-alpha baseline emission was reduced, both signatures of improved wall conditioning. A modest decrease in stored energy and normalized energy confinement was also observed, but the confinement relative to H98 remained well above 1, extending the previous ELM elimination results via Li injection into the lower carbon divertor in EAST [J.S. Hu et al., Phys. Rev. Lett. 114 (2015) 055001]. These results can be compared with recent observations with lithium pellets in ASDEX-Upgrade that failed to mitigate ELMs [P.T. Lang et al., Nucl. Fusion 57 (2017) 016030], highlighting one comparative advantage of continuous powder injection for real-time ELM elimination.readme, digital data file
ELM frequency enhancement and discharge modification through lithium granule injection into EAST H-modes
The injection of impurity granules into fusion research discharges can serve
as a catalyst for ELM events. For sufficiently low ELM frequencies, and granule
sizes above a threshold, this can result in full control of the ELM cycle,
referred to as ELM pacing. For this research, we extend the investigation
to conditions where the natural ELM frequency is too high for ELM pacing to
be realized. Utilizing multiple sizes of lithium granules and classifying their
effects by granule size, we demonstrate that ELM mitigation through frequency
multiplication can be used at ELM triggering rates that nominally make ELM pacing
unrealizable. We find that above a size threshold, injected granules promptly
trigger ELMs and commensurately enhance the ELM frequency . Below this threshold
size, injection of an individual granule does not always lead to the prompt
triggering of an ELM; however, collective ablation in the edge pedestal region
does enhance the ELM frequency. Specifically, Li granules too small to individually
trigger ELMs were injected into EAST H-mode discharges at frequencies up to 2.3 kHz;
collectively the granules were observed to enhance the natural ELM frequency up to
620 Hz, resulting in a ~2.4x multiplication of the natural ELM frequency and a 50%
decrease of the ELM size.readme and digitial data file