Observation of explosive collisionless reconnection in 3D nonlinear gyrofluid simulations

The nonlinear dynamics of collisionless reconnecting modes is investigated, in the framework of a three-dimensional gyrofluid model. This is the relevant regime of high-temperature plasmas, where reconnection is made possible by electron inertia and has higher growth rates than resistive reconnection. The presence of a strong guide field is assumed, in a background slab model, with Dirichlet boundary conditions in the direction of nonuniformity. Values of ion sound gyro-radius and electron collisionless skin depth much smaller than the current layer width are considered. Strong acceleration of growth is found at the onset to nonlinearity, while at all times the energy functional is well conserved. Nonlinear growth rates more than one order of magnitude higher than linear growth rates are observed when entering into the small-$\Delta'$ regime

A notion of rectifiability modeled on Carnot groups

We introduce a notion of rectifiability modeled on Carnot groups. Precisely, we say that a subset E of a Carnot group M and N is a subgroup of M, we say E is N-rectifiable if it is the Lipschitz image of a positive measure subset of N. First, we discuss the implications of N-rectifiability, where N is a Carnot group (not merely a subgroup of a Carnot group), which include N-approximability and the existence of approximate tangent cones isometric to N almost everywhere in E. Second, we prove that, under a stronger condition concerning the existence of approximate tangent cones isomorphic to N almost everywhere in a set E, that E is N-rectifiable. Third, we investigate the rectifiability properties of level sets of C^1_N functions, where N is a Carnot group. We show that for almost every real number t and almost every noncharacteristic point x in a level set of f, there exists a subgroup T_x of H and r >0 so that f^{-1}(t) intersected with B_H(x,r) is T_x-approximable at x and an approximate tangent cone isomorphic to T_x at x.Comment: 27 page

Dynamical Alignment in Three Species Tokamak Edge Turbulence

Three dimensional computations of self consistent three species gyrofluid turbulence are carried out for tokamak edge conditions. Profiles as well as disturbances in dependent variables are followed, running the dynamical system to transport equilibrium. The third species density shows a significant correlation with that of the electrons, regardless of initial conditions and drive mechanisms. For decaying systems the densities evolve toward each other. Companion tests with a simple two dimensional drift wave model show this persists even if the third species is a passively advected test field. Similarity in the transport character of electrons and the trace species does not imply that the electrons themselves have a test particle transport character.Comment: RevTeX 4, 21 pages, 15 figures, submitted to Physics of Plasma

Who Is a “Veteran”?—Basic Eligibility for Veterans’ Benefits

The U.S. Department of Veterans Affairs (VA) offers a broad range of benefits to veterans of the U.S. Armed Forces and to certain members of their families. Among these benefits are various types of financial assistance, including monthly cash payments to disabled veterans, health care, education, and housing. Certain criteria must be met to be eligible to receive any of the benefits administered by the VA. This report focuses on basic eligibility and entitlement requirements for former servicemembers for benefits administered by the VA. Certain VA benefits are available to current servicemembers, and the eligibility requirements for those benefits are not a component of this report. The VA uses a two-step process to evaluate claims for benefits. First, the claimant must demonstrate eligibility for veterans’ benefits in general. That is, the claimant must prove that he or she is a bona fide veteran and verify certain related matters. Second, the veteran must prove entitlement to the particular benefit being sought

Zonal Flows and Electromagnetic Drift Wave Turbulence

Detailed computations of tokamak edge turbulence in three dimensional, globally consistent flux tube geometry show an inhibition of the standard scenario in which zonal ExB flows generated by the turbulence should lead to transport barrier formation. It is found by comparison to slab geometry and by analysis of the energetics that the zonal flow energy is depleted by toroidal coupling to the pressure through the geodesic curvature. Edge transport barriers would then depend on the physics of the neoclassical equilibrium.Comment: 14 pages including 5 figures, submitted to Physics Letters

Social Security and Social Security Disability Insurance (SSDI) Provisions in the Bipartisan Budget Act of 2015

[Excerpt] Title VIII of the Bipartisan Budget Act of 2015 (H.R. 1314, P.L. 114-74) makes several changes to the Social Security programs. Among these changes is a temporary reallocation of the Social Security payroll taxes so that a larger share is deposited in the Disability Insurance (DI) trust fund to extend the life of this trust fund beyond its current predicted exhaustion in 2016. Under this provision, the allocation of the 12.40% Social Security payroll tax assigned to the DI trust fund increases from 1.80% to 2.37% and the allocation to the Old-Age and Survivors Insurance (OASI) trust fund decreases from 10.60% to 10.03%. These changes last through 2018. In addition, these provisions extend the Social Security Administration’s (SSA) demonstration authority for the Social Security Disability Insurance (SSDI) programs, make changes to data and earnings reporting, and increase penalties for benefit fraud. Title VIII of the act includes the following subtitles: Subtitle A. Ensuring Correct Payments and Reducing Fraud Subtitle B. Promoting Opportunity for Disability Beneficiaries Subtitle C. Protecting Social Security Benefits Subtitle D. Relieving Administrative Burdens and Miscellaneous Provision