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In an effort to measure electron-impact ionization (EII) cross-sections of He-like Fe24+ at the electron beam ion trap (EBIT) facility of the National Institute of Standards and Technology (NIST), we have experimentally determined the corrections to the nominal beam energy determined by the voltages applied to the EBIT. High-resolution X-ray spectra were recorded at nominal electron beam energies between 6660 eV and 6750 eV using X-ray microcalorimetry based upon an array of 192 transition-edge sensors (TES). A large-scale collisional-radiative simulation of the non-Maxwellian EBIT plasma using relevant atomic data calculated with Flexible Atomic Code allowed us to determine the space-charge correction due to the electron beam including the neutralization factor by the ion cloud of the EBIT.

This article is a critical review of publications devoted to studying the electrostatic interaction of two charged macroparticles in an equilibrium plasma. It is shown from an analysis of the force of interaction based on the Maxwell stress tensor that two macroparticles with identical charges in the Poisson–Boltzmann model always repel each other both in isothermal and nonisothermal plasmas. At distances between macroparticles for which the Boltzmann exponents can be linearized, the interaction between macroparticles is completely described by the Debye–Hückel model. The correction to free energy due to the electrostatic interaction in the system of two macroparticles is determined by integrating the correction to the internal energy and by direct calculation of the correction for entropy. It is shown that the free energy coincides with the Yukawa potential. The coincidence of the interaction energy obtained by integrating the force of interaction with the free energy leads to the conclusion about the potential nature of the force of interaction between two macroparticles in an equilibrium plasma. The effect of the outer boundary on the electrostatic interaction force is analyzed; it is shown that the type of interaction depends on the choice of the boundary conditions at the outer boundary. It is also shown that the accumulation of space charge near the outer boundary can lead to the attraction of similarly charged particles at distances comparable with the radius of the outer boundary.

In any hadron synchrotron, the half-integer resonance is among the strongest effects limiting the achievable maximum beam intensity. The heavy-ion superconducting synchrotron SIS100, currently under construction at GSI, should provide intense beams for the future FAIR experiments. Using SIS100 as an example, this paper develops a quantitative framework for characterizing the half-integer stop band for realistic, Gaussian-like distributed bunched beams. This study identifies the tune areas affected by the gradient-error-induced half-integer resonance for varying space charge strengths. A key insight of our analysis is that, for bunched beams a relatively small gradient error can result in a large half-integer stop band width. The achievable maximum bunch intensity, often referred to as space charge limit, is thus reduced significantly. This contrasts the findings in existing studies in literature based on more simplified beam distributions. The reason for discrepancy is identified in the increasing stop band width for Gaussian distributions when space charge becomes stronger, which appears on longer time scales as relevant for synchrotrons. The role of synchrotron motion in providing continuous emittance growth across the bunch is scrutinized. To minimize the half-integer stop band for a bunched beam, and hence increase the space charge limit, lattice corrections are applied: Including space charge in the optimization procedure recovers results equivalent to conventional lattice correction. Therefore, we find that conventional correction tools are well suited to increase the gradient-error-induced space charge limit of synchrotrons.

Measurements of thermal conduction in tokamaks parallel to the magnetic field were up to 20 times less than the classical values. This was explained by the quantum correction of the collision frequency of electrons with ions. This stowing effect of heat is applied to re-evaluate the ignition threshold for the energy flux density E* for the ignition of solid state density deuterium tritium using nonlinear (ponderomotive) laser force driven space charge neutral plasma blocks.