Beam induced electron cloud resonances in dipole magnetic fields

Electron Cyclotron Resonances in Electron Cloud Dynamics *

We report a previously unknown resonance for electron cloud dynamics. The 2D simulation code “POSINST” was used to study the electron cloud buildup at different z positions in the International Linear Collider positron damping ring wiggler. An electron equilibrium density enhancement of up to a factor of 3 was found at magnetic field values for which the bunch frequency is an integral multiple ...

Beam-Induced Multipactoring and Electron-Cloud Effects in Particle Accelerators

High-energy particle accelerators produce intense charged particle beams, e.g. of electrons or protons, at multi-GeV or multi-TeV energies, either shooting a single such beam against a fixed target or colliding two beams, in order to produce new particles and to study the scattering events in the search for the fundamental laws of physics. In the beam pipe of these accelerators an “electron clo...

Measurement of a magnetic-dipole transition probability in Xe 321 using an electron-beam ion trap

The transition probability for the 3d D2←D3 magnetic-dipole transition in Ti-like Xe ~Xe) has been measured using an electron-beam ion trap. The unusually weak dependence of the transition energy on nuclear charge Z , and the fact that the transition wavelength remains in the 320to 400-nm range for 54,Z,92, makes this transition promising as a plasma diagnostic tool. Our measurement of the tran...

Coupled Dipole Oscillations in an Intense Relativistic Electron Beam

Magnetic Fields in Molecular Cloud Cores

Observations of magnetic field strengths imply that molecular cloud fragments are individually close to being in a magnetically critical state, even though both magnetic field and column density measurements range over two orders of magnitude. The turbulent pressure also approximately balances the self-gravitational pressure. These results together mean that the one-dimensional velocity dispers...