BACKGROUND Techniques based on radio frequency (RF) energy have many applications in medicine, in particular tumour ablation. Today, mammography screening detects many breast cancers at an early stage, facilitating treatment by minimally invasive techniques such as radio frequency ablation (RFA). The breast cancer is mostly surrounded by fat, which during RFA-treatment could result in preferent...

Classical collisions with an ideal gas generate non-Maxwellian distribution functions for a single ion in a radio frequency ion trap. The distributions have power-law tails whose exponent depends on the ratio of buffer gas to ion mass. This provides a statistical explanation for the previously observed transition from cooling to heating. Monte Carlo results approximate a Tsallis distribution ov...

[1] Extremely low frequency/very low frequency (ELF/VLF) radio waves are difficult to generate with conventional antennas. Ionospheric high frequency (HF) heating facilities generate ELF/VLF waves via modulated heating of the lower ionosphere. HF heating of the ionosphere changes the lower ionospheric conductivity, which in the presence of natural currents such as the auroral electrojet creates...

Classical collisions with an ideal gas generate non-Maxwellian distribution functions for a single ion in a radio frequency ion trap. The distributions have power-law tails whose exponent depends on the ratio of buffer gas to ion mass. This provides a statistical explanation for the previously observed transition from cooling to heating. Monte Carlo results approximate a Tsallis distribution ov...

We report reliable transport of (9)Be(+) ions through an "X junction" in a 2D trap array that includes a separate loading and reservoir zone. During transport the ion's kinetic energy in its local well increases by only a few motional quanta and internal-state coherences are preserved. We also examine two sources of energy gain during transport: a particular radio-frequency noise heating mechan...

In respect of imaging quality and patient safety, temperature rises and SAR distributions, which are caused by interaction of the applied electromagnetic fields during MR exams, are of high interest for implants in MR tomography [1]. High local SAR values are equivalent to high local temperature increases [2]. For developing support for radio frequency (RF) induced heating experiments, SAR valu...

Assimilating radio-frequency waves with rays, this thesis examines the transport of electromagnetic power in a cold plasma, for heating and current-drive applications in tokamaks. Conservation laws are used to compute both the wave amplitude and phase in the Eikonal approximation and extend the RAYcON code to account for phenomena such as focusing until linear conversion is encountered. Simulat...

1. Introduction The studies of linear antenna in anisotropic mediums are important in such applications as radio communication in space, heating of plasma by high-frequency electromagnetic fields, diagnostics of magnetoactive plasma, electromagnetic compatibility of electronic devices, etc. The purpose of the present work is the solution of the problem on excitation of a system of thin impedanc...

In modern surgery, a multitude of minimally intrusive operational techniques are used which are based on the punctual heating of target zones of human tissue via laser or radio-frequency currents. Traditionally, these processes are modeled by the bioheat equation introduced by Pennes, who considers Fourier’s theory of heat conduction. We present an alternative and more realistic model establish...

Localized direct electron heating by mode-converted ion cyclotron range of frequencies (ICRF) waves in D(H) tokamak plasmas has been clearly observed for the first time in Alcator C-Mod. Both onand off-axis (high field side) mode conversion electron heating (MCEH) have been observed. The MCEH profile was obtained from a break in slope analysis of electron temperature signals in the presence of ...