Suppressed ion-scale turbulence in a hot high-ß plasma.

An economic magnetic fusion reactor favours a high ratio of plasma kinetic pressure to magnetic pressure in a well-confined, hot plasma with low thermal losses across the confining magnetic field. Field-reversed configuration (FRC) plasmas are potentially attractive as a reactor concept, achieving high plasma pressure in a simple axisymmetric geometry. Here, we show that FRC plasmas have unique, beneficial microstability properties that differ from typical regimes in toroidal confinement devices. Ion-scale fluctuations are found to be absent or strongly suppressed in the plasma core, mainly due to the large FRC ion orbits, resulting in near-classical thermal ion confinement. In the surrounding boundary layer plasma, ion- and electron-scale turbulence is observed once a critical pressure gradient is exceeded. The critical gradient increases in the presence of sheared plasma flow induced via electrostatic biasing, opening the prospect of active boundary and transport control in view of reactor requirements.

Diagnostic suite of the C-2U advanced beam-driven field-reversed configuration plasma experiment.

The C-2U experiment at Tri Alpha Energy studies the evolution of field-reversed configuration (FRC) plasmas sustained by neutral beam injection. Data on the FRC plasma performance are provided by a comprehensive suite of diagnostics that includes magnetic sensors, interferometry, Thomson scattering, spectroscopy, bolometry, reflectometry, neutral particle analyzers, and fusion product detectors. While many of these diagnostic systems were inherited from the preceding experiment C-2, C-2U has a variety of new and upgraded diagnostic systems: multi-chord far-infrared polarimetry, multiple fast imaging cameras with selectable atomic line filters, proton detector arrays, and 100 channel bolometer units capable of observing multiple regions of the spectrum simultaneously. In addition, extensive ongoing work focuses on advanced methods of measuring separatrix shape and plasma current profile that will facilitate equilibrium reconstruction and active control of the FRC plasma.

Far infrared laser polarimetry and far forward scattering diagnostics for the C-2 field reversed configuration plasmas.

A two-chord far infrared (FIR) laser polarimeter for high speed sub-degree Faraday rotation measurements in the C-2 field reversed configuration experiment is described. It is based on high power proprietary FIR lasers with line width of about 330 Hz. The exceptionally low intrinsic instrument phase error is characterized with figures of merit. Significant toroidal magnetic field with rich dynamics is observed. Simultaneously obtained density fluctuation spectra by far forward scattering are presented.

Overview of C-2 field-reversed configuration experiment plasma diagnostics.

A comprehensive diagnostic suite for field-reversed configuration (FRC) plasmas has been developed and installed on the C-2 device at Tri Alpha Energy to investigate the dynamics of FRC formation as well as to understand key FRC physics properties, e.g., confinement and stability, throughout a discharge. C-2 is a unique, large compact-toroid merging device that produces FRC plasmas partially sustained for up to ∼5 ms by neutral-beam (NB) injection and end-on plasma-guns for stability control. Fundamental C-2 FRC properties are diagnosed by magnetics, interferometry, Thomson scattering, spectroscopy, bolometry, reflectometry, and NB-related fast-ion/neutral diagnostics. These diagnostics (totaling >50 systems) are essential to support the primary goal of developing a deep understanding of NB-driven FRCs.

Multi-channel Doppler backscattering measurements in the C-2 field reversed configuration.

A versatile heterodyne Doppler Backscattering (DBS) system is used to measure density fluctuation levels (in the wavenumber range kρs ≤ 50), and the toroidal E × B flow velocity in the C-2 Field-Reversed Configuration (FRC). Six tunable frequencies in three waveguide bands (26 GHz ≤ f ≤ 90 GHz) are launched using monostatic beam optics, via a quasi-optical beam combiner/polarizer and an adjustable parabolic focusing mirror (inside the vacuum enclosure) achieving Gaussian beam spot sizes of 3-5.5 cm at the X/O-mode cutoff. The DBS system covers plasma densities of 0.8 × 10(13) ≤ ne ≤ 1 × 10(14) cm(-3), and provides access to the FRC core (up to the field null) and across the FRC separatrix into the scrape-off layer plasma.

Internal magnetic field measurement on C-2 field-reversed configuration plasmas.

A long-lived field-reversed configuration (FRC) plasma has been produced in the C-2 device by dynamically colliding and merging two oppositely directed, highly supersonic compact toroids (CTs). The reversed-field structure of the translated CTs and final merged-FRC state have been directly verified by probing the internal magnetic field structure using a multi-channel magnetic probe array near the midplane of the C-2 confinement chamber. Each of the two translated CTs exhibits significant toroidal fields (B(t)) with opposite helicity, and a relatively large B(t) remains inside the separatrix after merging.

Magnetic diagnostic suite of the C-2 field-reversed configuration experiment confinement vessel.

Magnetic measurements are a fundamental part of determining the size and shape of field-reversed configuration (FRC) plasmas in the C-2 device. The magnetic probe suite consists of 44 in-vessel and ex-vessel probes constructed using various technologies: ultra-high vacuum compatible mineral-insulated cable, nested triple axis coils hand-wound on ceramic bobbins, and commercial chip inductors mounted on printed circuit boards. Together, these probes measure the three-dimensional excluded flux profile of the FRC, which approximates the shape of the separatrix between the confined plasma volume and the scrape-off layer. High accuracy is achieved by using the extensive probe measurements to compensate for non-ideal effects such as flux leakage through the vacuum vessel and bulk motion of the FRC towards the wall. A subset of the probes is also used as a set of Mirnov arrays that provide sensitive detection of perturbations and oscillations of the FRC.

Field reversed configuration confinement enhancement through edge biasing and neutral beam injection.

Field reversed configurations (FRCs) with high confinement are obtained in the C-2 device by combining plasma gun edge biasing and neutral beam injection. The plasma gun creates an inward radial electric field that counters the usual FRC spin-up. The n = 2 rotational instability is stabilized without applying quadrupole magnetic fields. The FRCs are nearly axisymmetric, which enables fast ion confinement. The plasma gun also produces E × B shear in the FRC edge layer, which may explain the observed improved particle transport. The FRC confinement times are improved by factors 2 to 4, and the plasma lifetimes are extended from 1 to up to 4 ms.

Two-color CO2/HeNe laser interferometer for C-2 experiment.

A six-channel two-color interferometer has been developed for plasma electron density measurements in the C-2 field reversed configuration experiment. A CO(2) laser is utilized as the main probe beams, while copropagating visible HeNe laser beams are mainly sensitive to vibration. Density measurements in C-2 plasmas have shown that this is a reliable turn-key system. The maximum residual phase noise after vibration compensation is less than ±5°, corresponding to a line integral density of 3×10(18) m(-2). The time resolution for routine operation is 2 µs.

Doppler spectroscopy and D-alpha emission diagnostics for the C-2 FRC plasma.

Two Doppler spectroscopy diagnostics with complementary capabilities are developed to measure the ion temperatures and velocities of FRC plasmas in the C-2 device. First, the multichord ion doppler diagnostic can simultaneously measure 15 chords of the plasma using an image intensified camera. Second, a single-chord fast-response ion Doppler diagnostic provides much higher faster time response by using a 16-channel photo-multiplier tube array. To study the neutral density of deuterium under different wall and plasma conditions, a highly sensitive eight-channel D-alpha diagnostic has been developed and calibrated for absolute radiance measurements. These spectroscopic diagnostics capabilities, combined with other plasma diagnostics, are helping to understand and improve the field reversed configuration plasmas in the C-2 device.

Dynamic formation of a hot field reversed configuration with improved confinement by supersonic merging of two colliding high-ß compact toroids.

A hot stable field-reversed configuration (FRC) has been produced in the C-2 experiment by colliding and merging two high-ß plasmoids preformed by the dynamic version of field-reversed θ-pinch technology. The merging process exhibits the highest poloidal flux amplification obtained in a magnetic confinement system (over tenfold increase). Most of the kinetic energy is converted into thermal energy with total temperature (T{i}+T{e}) exceeding 0.5 keV. The final FRC state exhibits a record FRC lifetime with flux confinement approaching classical values. These findings should have significant implications for fusion research and the physics of magnetic reconnection.

Nested polymerase chain reaction strategy simultaneously targeting DNA sequences of multiple bacterial species in inflammatory joint diseases. I. Screening of synovial fluid samples of patients with spondyloarthropathies and other arthritides.

OBJECTIVE: Bacteria play a crucial pathogenetic role in Lyme arthritis (LA), reactive arthritis (ReA), other forms of spondyloarthropathy (SpA), and possibly in undifferentiated oligoarthritis (uOligo). Polymerase chain reaction (PCR) technology has been applied to detect bacterial DNA of individual microbes in synovial fluid (SF) of patients with arthritides. We screened for DNA sequences of 8 bacterial species simultaneously in SF of patients with inflammatory joint disease. METHODS: We examined 104 SF samples of 96 patients with ReA (n = 13), undifferentiated SpA (uSpA, n = 10), uOligo (n = 50), juvenile chronic arthritis (JCA, n = 13), and rheumatoid arthritis (RA, n = 10). A nested PCR approach was developed to detect DNA sequences of 8 bacteria: Chlamydia trachomatis, C. pneumoniae, Yersinia enterocolitica, Salmonella enteritidis, Campylobacter jejuni, Shigella flexneri, Klebsiella pneumoniae, and Borrelia burgdorferi. The detection limit was determined at 10 bacterial/sample. Serology and lymphocyte proliferation assay were done in parallel in most patients. RESULTS: In 12 cases bacterial DNA of B. burgdorferi (n = 7), C. trachomatis (n = 2), C. jejuni (n = 2), and C. pneumoniae (n = 1) was detected in patients with uOligo (n = 9) and JCA (n = 3), while no evidence of bacterial DNA was found in patients with ReA, uSpA, and RA. Shigella flexneri DNA was detected in 4 cases, but the significance of this finding remains uncertain due to the high sequence homology of this species with Escherichia coli. DNA of Y. enterocolitica, S. enteritidis, or K. pneumoniae was not found. A positive serologic response was found in 7/9 PCR positive patients. In 11/96 cases antibodies to 2 or more bacteria were found in parallel (11.5%). Antigen specific lymphocyte proliferation was observed in 5/9 PCR positive patients. CONCLUSION: Bacterial DNA was detected in peripheral joint of patients with uOligo and JCA, but not in ReA, uSpA, or RA in this study. The detection of bacterial DNA in synovial material by PCR technology gives useful diagnostic information, especially when antibodies against several microbes are present or antibodies are not detectable. Failure to detect bacterial DNA in patients with ReA and uSpA with longstanding disease suggests that in later stages autoimmune mechanisms may operate.

Nested polymerase chain reaction strategy simultaneously targeting DNA sequences of multiple bacterial species in inflammatory joint diseases. II. Examination of sacroiliac and knee joint biopsies of patients with spondyloarthropathies and other arthritides.

OBJECTIVE: Bacteria play a crucial pathogenetic role in reactive arthritis (ReA) and other forms of spondyloarthropathy (SpA) and in Lyme arthritis. Although there is evidence of local persistence of bacterial antigens no definitive method revealing microbes in peripheral joints has been established. We detected DNA of individual bacteria in synovial material by PCR. Applying molecular technology we screened simultaneously for 8 bacterial genomes in arthritis and sacroiliitis. METHODS: Sacroiliac (SI) biopsy specimens taken from the SI joint of 8 patients with ankylosing spondylitis (AS, n = 5) and undifferentiated SpA (uSpA, n = 3) by computed tomography guided biopsy were investigated for presence of bacterial DNA. Similarly, synovial membrane samples obtained by office arthroscopy from 15 patients with ReA (n = 5), uSpA (n = 3), undifferentiated oligoarthritis (uOligo, n = 3), and rheumatoid arthritis (RA, n = 4) were screened. Nested PCR was performed for DNA of the following bacteria: Chlamydia trachomatis, C. pneumoniae, Yersinia enterocolitica, Salmonella enteritidis, Campylobacter jejuni, Shigella flexneri, Klebsiella pneumoniae, and Borrelia burgdorferi. RESULTS: No bacterial DNA was found in the SI biopsies of patients with uSpA and AS. DNA of B. burgdorferi (n = 2) and C. trachomatis (n = 1) was detected in 3 patients with uOligo, but not in patients with ReA or RA. DNA of other microbes including K. pneumoniae was not found. Patients' mean disease duration was 5.3 years (2 mo-8.4 yrs). CONCLUSION: We found bacterial DNA in peripheral joints of patients with uOligo, while in patients with ReA, AS, and uSpA no bacterial DNA was detected in peripheral or SI joints. The failure to detect bacterial DNA in patients with SpA suggests autoimmune mechanisms operate in later stages of disease.

[Surgical treatment of idiopathic megacolon]. / Leczenie chirurgiczne samoistnej postaci jelita olbrzymiego.

The authors discuss own experience in diagnosis and surgical treatment of 32 patients with idiopathic megacolon. Three surgical techniques were compared: 1) partial excision of the colon, 2) nearly complete excision of the colon with cecum-rectal anastomosis, and 3) total colectomy with ileorectal anastomosis. Basing on the authors' own experience and available literature the third approach is recommended as the most appropriate in the treatment of the persistent, chronic constipation accompanying idiopathic megacolon.

[Comparative evaluation of tensile strength of absorbable threads Dexon and Maxon. Experimental studies]. / Ocena porównawcza wytrzymalosci na zrywanie syntetycznych nici wchlanialnych Dexon i Maxon. Badania doswiadczalne.

This paper submits strength tests on Dexon and Maxon resorbable sutures at the knot and without a knot, the breaking resulting from hydrolysis. The tests were performed on rats, by comparing Maxon monofilament suture with Dexon woven suture. The dissections were done 3, 7, 21 and 42 days after the implantation. What we found out was a remarkably slower process of strength loss displayed by Maxon sutures in time after the implantation. After 21 days, Dexon sutures displayed a minimal strength value, whereas Maxon sutures still retained ca 60% of the initial properties.

[Evaluation of the analgesic effectiveness of tramadol hydrochloride in surgical practice]. / Ocena skutecznosci przeciwbólowej chlorowodorku trama-dolu w praktyce chirurgicznej.

Tramadol hydrochloride was administered to: a) 90 patients who underwent various abdominal surgery (group A) immediately after operation; b) 50 patients with inoperable tumors of pharynx, stomach, pancreas, liver and biliary tract and colon (group B); c) 32 patients in surgical out-patient clinic (group C). Excellent and favourable results (group A - 87.8%; group B - 74%, and group C - 75%) and negligible adverse reactions advocate the use of tramadol hydrochloride both in in- and out-patient surgical clinics as an effective analgesic agent.