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Chirping toroidicity-induced Alfvén eigenmodes (TAEs) are destabilized during neutral beam injection on the National Spherical Torus Experiment (NSTX (Ono M. et al 2000 Nucl. Fusion 40 557)) by super-Alfvénic ions with velocities up to five times larger than the Alfvén velocity. TAEs exhibit repeated bursts in amplitude and down-chirps in frequency. Larger bursts, so-called TAE avalanches, are eventually observed and correlate with a loss of fast ions up to 30% over ∼1ms. Frequency, amplitude and radial structure of TAEs are characterized via magnetic pickup coils and a multi-channel reflectometer system. The modes have a broad radial structure, which appears to be unaffected by the large frequency and amplitude variations. However, the large mode amplitude does impact the modes' dynamics by favouring the coupling among different modes. In addition, the coupling involves kink-like modes and can therefore degrade the thermal plasma confinement. In spite of the non-linear regime characterizing the TAE dynamics, the measured properties are found to be in reasonable agreement with solutions from the ideal MHD code NOVA. © 2012 IAEA, Vienna.

Kinetic theory and experimental observations of a special class of energetic particle driven instabilities called here beta-induced Alfv́n-acoustic eigenmodes (BAAEs) are reported confirming, previous results [N. N. Gorelenkov, Plasma Phys. Controlled Fusion 49, B371 (2007)]. The kinetic theory is based on the ballooning dispersion relation where the drift frequency effects are retained. BAAE gaps are recovered in kinetic theory. It is shown that the observed certain low-frequency instabilities on DIII-D [J. L. Luxon, Nucl. Fusion 42, 614 (2002)] and National Spherical Torus Experiment [M. Ono, S. M. Kaye, Y.-K. M. Peng, Nucl. Fusion 40, 557 (2000)] are consistent with their identification as BAAEs. BAAEs deteriorate the fast ion confinement in DIII-D and can have a similar effect in next-step fusion plasmas, especially if excited together with multiple global toroidicity-induced shear Alfv́n eigenmode instabilities. BAAEs can also be used to diagnose safety factor profiles, a technique known as magnetohydrodynamic spectroscopy. © 2009 American Institute of Physics.

The stability of α-particle driven shear Alfvén eigenmodes (AE) for nominal burning plasma (BP) parameters in the proposed international tokamak experimental reactor (ITER), fusion ignition research experiment (FIRE) and IGNITOR tokamaks is studied. JET plasma, where fusion as were generated in tritium experiments, is also studied to compare the numerical predictions with the existing experiments. An analytic assessment of toroidal AE (TAB) stability is first presented, where the α-particle β due to the fusion reaction rate and electron drag is simply and accurately estimated in plasmas with central temperature in the range of 7-20 keV. In this assessment the hot particle drive is balanced against ion-Landau damping of the background douterons, and electron collision effects and stability boundaries are determined. Then two numerical studies of AE instability are presented. In one, the HIgh-n STability (HINST) code is used to predict the instabilities of low and moderately high frequency Alfvén modes. HINST computes the non-perturbative solutions of the AE including effects of ion finite Larmor radius, orbit width, trapped electrons etc. The stability calculations are repeated using the global code NOVAK. We show that for these plasmas the spectrum of the least stable AE modes is at medium-/high-n numbers. In HINST, TAEs are locally unstable due to the α pressure gradient in all the devices under consideration except IGNITOR. However, NOVAK calculations show that the global mode structure enhances the damping mechanisms and produces stability for the nominal FIRE proposal and near-marginal stability for the nominal ITER proposal. NBI ions produce a strong stabilizing effect for JET. However, in ITER, the beam energies needed to penetrate to the core must be high (∼1 MeV) so that a diamagnetic drift frequency comparable to that of α-particles is produced by the beam ions which induces a destabilizing effect. A serious question remains whether the perturbation theory used in NOVAK overestimates the stability predictions, so that it is premature to conclude that the nominal operation of all three BP proposals without neutral beam injection are stable (or marginally stable) to AEs.

Introduction: The conversion from intravenous (IV) to subcutaneous (SC) delivery of biotherapeutics has increased in recent years. Some of the reasons for this shift in route of delivery are due to patient convenience, reduced adverse systemic effects, lack of a need for vascular access, and reduced cost of patient care, which ultimately lead to improved patient quality of life. One caveat to SC delivery is the limited volumes that can be administered at a single site and the associated local tolerability. To characterize factors that affect subcutaneous delivery of large volumes of therapeutic proteins, a porcine model was developed. Model endpoints included measurement of interstitial pressure, assessment of local skin visco-elasticity, and the qualitative assessment of local infusion sites., Methods: Immunoglobulin G (IgG) was subcutaneously infused into the abdominal region of Yucatan miniature swine. Changes in interstitial pressure were measured, using an in-line pressure transducer, during and after infusions. Additionally, pre- and post-infusion changes in local skin visco-elasticity were measured using a Cutometer®. Lastly, infusion sites were assessed for post-infusion local skin reactions such as erythema and swelling. Similar assessments were made following SC IgG delivery with the permeation enhancer recombinant human hyaluronidase PH20 (rHuPH20)., Results: Subcutaneous infusions of IgG, in the presence of rHuPH20, significantly reduced average interstitial pressures by 55% during the infusion period and by 67% during the post-infusion period, compared to the control. Infusions in the presence of rHuPH20 also maintained better local skin elasticity as seen by a 42% increase in local skin pliability compared to the control. Finally, infusions with rHuPH20 resulted in an 80% reduction in swelling area compared to the control., Discussion: A large animal model was developed that incorporates both quantitative and qualitative assessment methods to aid in understanding SC delivery of proteins., (Copyright © 2013 Elsevier Inc. All rights reserved.)

Hypertrophic cardiomyopathy predisposes patients to atrial fibrillation and the development of systemic embolization. We describe a rare case of bilateral renal artery thrombosis which presented as acute renal failure requiring dialysis. The patient was successfully treated with a selective, continuous infusion of urokinase which resulted in the return of adequate renal function.