| Paper |
Title |
Page |
| WEAY04 |
Analysis of the magnetized friction force
|
210 |
| |
- A. V. Fedotov
BNL, Upton, Long Island, New York
- D. L. Bruhwiler
Tech-X, Boulder, Colorado
- A. O. Sidorin
JINR, Dubna, Moscow Region
|
|
| |
A comprehensive examination of theoretical models for the friction force, in use by the electron cooling community, was performed. Here, we present our insights about the models gained as a result of comparison between the friction force formulas and direct numerical simulations, as well as studies of the cooling process as a whole.
|
|
| WEBY03 |
Experimental studies of IBS in RHIC and comparison with theory
|
259 |
| |
- A. V. Fedotov, W. Fischer, S. Tepikian, J. Wei
BNL, Upton, Long Island, New York
|
|
| |
A high-energy electron cooling system is presently being developed to overcome emittance growth due to Intra-beam Scattering (IBS) for heavy ion operation in RHIC. A critical item for choosing appropriate parameters of the cooler is an accurate description of the IBS. The analytic models were verified vs dedicated IBS measurements. Analysis of the 2004 data with the Au ions showed very good agreement for the longitudinal growth rates but significant disagreement with exact IBS models for the transverse growth rates. Experimental measurements were improved for the 2005 run with the Cu ions. Here, we present comparison of the 2005 data with theoretical models.
|
|
| WEBY05 |
Simulating dynamical friction in wiggler-based high-energy electron coolers, including finite-time effects
|
0 |
| |
- G. I. Bell, D. T. Abell, D. L. Bruhwiler, R. Busby, P. Messmer
Tech-X, Boulder, Colorado
- I. Ben-Zvi, A. V. Fedotov, V. Litvinenko
BNL, Upton, Long Island, New York
- A. O. Sidorin
JINR, Dubna, Moscow Region
|
|
| |
The proposed RHIC-II luminosity upgrade includes a novel electron cooling section, using ~55 MeV electrons to cool fully-ionized gold. We present simulations of the dynamical friction force exerted on the Au ions. Rather than a strong solenoid, a long helical wiggler magnet is used to provide focusing and suppress recombination. In the rest frame of the relativistic electron and ion beams, with non-relativistic motion and electrostatic fields, the Lorentz transformed wiggler field yields strong, rapidly-varying electric fields. The VORPAL simulation framework applies a semi-analytic binary collision algorithm, in which ion-electron collisions are modeled pairwise. This model is combined with standard particle-in-cell (PIC) techniques, through an operator-splitting approach, to include the effects of external fields. Charge shielding due to electron-electron interactions is also included via PIC. Simulated friction results are compared with BETACOOL, which integrates the standard unmagnetized formulas. With finite interaction times and electron wiggle motion correctly included, we find good agreement with VORPAL.
|
|
| FRAP05 |
Summary of Working Group D
|
372 |
| |
- A. V. Fedotov, J. Wei
BNL, Upton, Long Island, New York
- I. N. Meshkov
JINR, Dubna, Moscow Region
|
|