T. M. Antonsen

Learn More
We introduce a new, alternative form of the 3D alternating direction implicit finite-difference time-domain (ADI- FDTD) algorithm that has a number of attractive properties for electromagnetic simulation. We obtain a leapfrog form of the time advance equations, where the E- and H- fields are staggered at half-integer and integer time steps respectively,(More)
A sequence of femtosecond laser pulses propagating through atmosphere and delayed near the rotational recurrence period of N 2 can resonantly drive molecular alignment. Through the polarization density, the molecular alignment provides an index of refraction contribution that acts as a lens copropagating with each laser pulse. Each pulse enhances this(More)
A laser pulse propagating in a corrugated plasma channel is composed of spatial harmonics whose phase velocities can be subluminal. The phase velocity of a spatial harmonic can be matched to the speed of a relativistic electron resulting in direct acceleration by the guided laser field in a plasma waveguide and linear energy gain over the interaction(More)
In this paper, we present a hybrid statistical model for confined electromagnetic environments with arbitrary geometry, coupled by electrically wide apertures, in presence of spatially localized sources and sinks. An external (oblique) plane wave is supposed to illuminate the aperture, which radiates inside a wave-chaotic cavity with distributed losses. The(More)
A laser pulse propagating through the atmosphere self-focuses due to the nonlinear index of refraction modifications from the instantaneous electronic and delayed rotational responses of the air molecules. If the pulse power is sufficient, the focused pulse intensity can surpass the ionization threshold, resulting in a plasma filament. The balance between(More)
The electromagnetic stress onto circuitry inside enclosures is a complicated process made of several coupling paths originated by multiple sources. Those sources are treated as equivalent apertures, and the cavity is assumed to have irregular boundaries. Then, a statistical description relying on wave-chaos theory is more appropriate to describe the(More)
The numerical simulation of electromagnetic fields and particle interactions in accelerator components can consume considerable computational resources. By performing the same computation on fast, highly parallel GPU hardware instead of conventional CPUs it is possible to achieve a 20x reduction in simulation time for the traditional 3D FDTD algorithm. For(More)
This paper presents analysis of the effects of nonperiodic perturbations in periodic RF structures. Small departures from periodicity change the phase shift experienced by a wave as it traverses an imperfect cell. Cell imperfections may be introduced intentionally or due to fabrication errors or material properties variations. The cumulative effect produces(More)
We present a parallelization framework prototype for efficient physics-based computer simulation of hyperspectral time-dependent waveforms (i.e., wideband with a large number of frequency components) in nonlinear power amplifiers with memory. It relies on an adaptive algorithm for signal splitting and splicing in the time domain and uses a well-established(More)