The nasopharynx (NP) is a reservoir for microbes associated with acute respiratory illnesses (ARI). The development of asthma is initiated during infancy, driven by airway inflammation associated with infections. Here, we report viral and bacterial community profiling of NP aspirates across a birth cohort, capturing all lower respiratory illnesses during their first year. Most infants were initially colonized with Staphylococcus or Corynebacterium before stable colonization with Alloiococcus or Moraxella, with transient incursions of Streptococcus, Moraxella or Haemophilus marking virus-associated ARIs. Our data identify the NP microbiome as a determinant for infection spread to the lower airways, severity of accompanying inflammatory symptoms, and risk for future asthma development. Early asymptomatic colonization with Streptococcus was a strong asthma predictor, and antibiotic usage disrupted asymptomatic colonization patterns.

A practical method for performing a tokamak equilibrium reconstruction in real time for arbitrary time-varying discharge shapes and current profiles is described. An approximate solution to the Grad-Shafranov equilibrium relation is found which best fits the diagnostic measurements. Thus a solution for the spatial distribution of poloidal flux and toroidal current density is available in real time that is consistent with plasma force balance, allowing accurate evaluation of parameters such as discharge shape and safety factor profile. The equilibrium solutions are produced at a rate sufficient for discharge control. This equilibrium reconstruction algorithm has been implemented on the digital plasma control system for the DIII-D tokamak. The first application of a real time equilibrium reconstruction to discharge shape control is described.

The basic question of nonlinear H" control theory is to decide, for a given two port system, when does feedback exist which makes the full system dissipative and internally stable. This problem can also be viewed as an interesting question about circuits. Also, after translation, the problem has a game theoretic statement. This paper presents several necessary conditions for solutions to exist and gives sufficient conditions for a certain construction to lead to a solution.

Plasma discharges with negative triangularity (δ = −0.4) shape have been created in the DIII-D tokamak with significant normalized beta (βN = 2.7) and confinement characteristic of the high confinement mode (H98y2 = 1.2) despite the absence of an edge pressure pedestal and no edge localized modes (ELMs). These inner-wall-limited plasmas have similar global performance as a positive triangularity (δ = +0.4) ELMing H-mode discharge with the same plasma current, elongation and cross-sectional area. For cases both of dominant electron cyclotron heating with Te/Ti > 1 and dominant neutral beam injection heating with Te/Ti = 1, turbulent fluctuations over radii 0.5 < ρ < 0.9 were reduced by 10-50% in the negative triangularity shape compared to the matching positive triangularity shape, depending on radius and conditions.

This is a preprint of a paper intended for publication in a journal or proceedings. Since changes may be made before publication, this preprint is made available with the understanding that it will not be cited or reproduced without the permission of the author.

Abstract. Recent DIII-D experiments show that ideal kink modes can be stabilized at high beta by a resistive wall, with sufficient plasma rotation. However, the resonant response by a marginally stable resistive wall mode to static magnetic field asymmetries can lead to strong damping of the rotation. Careful reduction of such asymmetries has allowed plasmas with beta well above the ideal MHD nowall limit, and approaching the ideal-wall limit, to be sustained for durations exceeding one second. Feedback control can improve plasma stability by direct stabilization of the resistive wall mode or by reducing magnetic field asymmetry. Assisted by plasma rotation, direct feedback control of resistive wall modes with growth rates more than 5 times faster than the characteristic wall time has been observed. These results open a new regime of tokamak operation above the free-boundary stability limit, accessible by a combination of plasma rotation and feedback control.

Abstract. Operating experimental devices have provided key inputs to the design process for ITER axisymmetric control. In particular, experiments have quantified controllability and robustness requirements in the presence of realistic noise and disturbance environments, which are difficult or impossible to characterize with modeling and simulation alone. This kind of information is particularly critical for ITER vertical control, which poses the highest demands on poloidal field system performance, since the consequences of loss of vertical control can be

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