Observation and Control of Hamiltonian Chaos in Wave-particle Interaction

Journal Article · Tue Nov 23 00:00:00 EST 2010 · AIP Conference Proceedings

DOI:https://doi.org/10.1063/1.3526149· OSTI ID:21506907

Doveil, F; Ruzzon, A ^[1]; Elskens, Y ^[1]

---

1. Turbulence Plasma, PIIM, UMR6633 CNRS/Universite de Provence, case 321, Centre universitaire de Saint Jerome, FR-13397 Marseilles cedex 20 (France)

Wave-particle interactions are central in plasma physics. The paradigm beam-plasma system can be advantageously replaced by a traveling wave tube (TWT) to allow their study in a much less noisy environment. This led to detailed analysis of the self-consistent interaction between unstable waves and an either cold or warm electron beam. More recently a test cold beam has been used to observe its interaction with externally excited wave(s). This allowed observing the main features of Hamiltonian chaos and testing a new method to efficiently channel chaotic transport in phase space. To simulate accurately and efficiently the particle dynamics in the TWT and other 1D particle-wave systems, a new symplectic, symmetric, second order numerical algorithm is developed, using particle position as the independent variable, with a fixed spatial step.This contribution reviews: presentation of the TWT and its connection to plasma physics, resonant interaction of a charged particle in electrostatic waves, observation of particle trapping and transition to chaos, test of control of chaos, and description of the simulation algorithm.The velocity distribution function of the electron beam is recorded with a trochoidal energy analyzer at the output of the TWT. An arbitrary waveform generator is used to launch a prescribed spectrum of waves along the 4m long helix of the TWT. The nonlinear synchronization of particles by a single wave, responsible for Landau damping, is observed. We explore the resonant velocity domain associated with a single wave as well as the transition to large scale chaos when the resonant domains of two waves and their secondary resonances overlap. This transition exhibits a devil's staircase behavior when increasing the excitation level in agreement with numerical simulation.A new strategy for control of chaos by building barriers of transport in phase space as well as its robustness is successfully tested. The underlying concepts extend far beyond the field of electron devices and plasma physics.

• OSTI ID: 21506907
• Journal Information: AIP Conference Proceedings, Vol. 1308, Issue 1; Conference: International symposium on waves, coherent structures and turbulence in plasmas, Gandhinagar (India), 12-15 Jan 2010; Other Information: DOI: 10.1063/1.3526149; (c) 2010 American Institute of Physics; ISSN 0094-243X
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS
ALGORITHMS
BEAM-PLASMA SYSTEMS
CHAOS THEORY
CHARGED PARTICLES
COMPUTERIZED SIMULATION
DISTRIBUTION FUNCTIONS
ELECTRON BEAMS
ELECTRONS
EXCITATION
EXCITED STATES
HAMILTONIANS
LANDAU DAMPING
PARTICLE INTERACTIONS
PHASE SPACE
PLASMA
PLASMA WAVES
RESONANCE
SYMMETRY
TRAVELLING WAVE TUBES
WAVE FORMS
BEAMS
DAMPING
ELECTRON TUBES
ELECTRONIC EQUIPMENT
ELEMENTARY PARTICLES
ENERGY LEVELS
ENERGY-LEVEL TRANSITIONS
EQUIPMENT
FERMIONS
FUNCTIONS
INTERACTIONS
LEPTON BEAMS
LEPTONS
MATHEMATICAL LOGIC
MATHEMATICAL OPERATORS
MATHEMATICAL SPACE
MATHEMATICS
MICROWAVE EQUIPMENT
MICROWAVE TUBES
PARTICLE BEAMS
QUANTUM OPERATORS
SIMULATION
SPACE