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Title: Intense Ion Beam for Warm Dense Matter Physics

Thesis/Dissertation ·
DOI:https://doi.org/10.2172/929701· OSTI ID:929701
 [1]
  1. Univ. of California, Berkeley, CA (United States)

The Neutralized Drift Compression Experiment (NDCX) at Lawrence Berkeley National Laboratory is exploring the physical limits of compression and focusing of ion beams for heating material to warm dense matter (WDM) and fusion ignition conditions. The NDCX is a beam transport experiment with several components at a scale comparable to an inertial fusion energy driver. The NDCX is an accelerator which consists of a low-emittance ion source, high-current injector, solenoid matching section, induction bunching module, beam neutralization section, and final focusing system. The principal objectives of the experiment are to control the beam envelope, demonstrate effective neutralization of the beam space-charge, control the velocity tilt on the beam, and understand defocusing effects, field imperfections, and limitations on peak intensity such as emittance and aberrations. Target heating experiments with space-charge dominated ion beams require simultaneous longitudinal bunching and transverse focusing. A four-solenoid lattice is used to tune the beam envelope to the necessary focusing conditions before entering the induction bunching module. The induction bunching module provides a head-to-tail velocity ramp necessary to achieve peak axial compression at the desired focal plane. Downstream of the induction gap a plasma column neutralizes the beam space charge so only emittance limits the focused beam intensity. We present results of beam transport through a solenoid matching section and simultaneous focusing of a singly charged K+ ion bunch at an ion energy of 0.3 MeV. The results include a qualitative comparison of experimental and calculated results after the solenoid matching section, which include time resolved current density, transverse distributions, and phase-space of the beam at different diagnostic planes. Electron cloud and gas measurements in the solenoid lattice and in the vicinity of intercepting diagnostics are also presented. Finally, comparisons of improved experimental and calculated axial focus (> 100 x axial compression, < 2 ns pulses) and higher peak energy deposition on target are also presented. These achievements demonstrate the capabilities for near term target heating experiments to Te ~ 0.1 eV and for future ion accelerators to heat targets to Te> 1 eV.

Research Organization:
Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
Sponsoring Organization:
USDOE Office of Science (SC), Fusion Energy Sciences (FES)
DOE Contract Number:
AC02-05CH11231
OSTI ID:
929701
Report Number(s):
LBNL-342E; TRN: US0803516
Resource Relation:
Related Information: Designation of Academic Dissertation: doctoral; Academic Degree: Doctor of Philosophy; Name of Academic Institution: UCB; Location of Academic Institution: Berkeley
Country of Publication:
United States
Language:
English