We report noise data for discontinuous Ni82Fe18/Ag multilayer test structures. Examination of the noise data for this material indicates that random telegraph fluchator (RTF) noise of the resistance is the predominant noise source. Analysis of the RTF noise in these structures presents an opportunity to estimate magnetic domain or magnetic cluster strengths and the domain-domain interactions.

Neutral particle density profiles have previously been calculated for spheromak plasmas [Phys. Fluids B 2 (1990) 115]. Here, the formalism is extended to calculate the one-dimensional (1-D) profile of the egressing neutral energy flux to correctly treat profile and attenuation effects. If is found that the energy flux profile is strongly dependent on Ti,Te,ne profiles and magnitudes, and regions of the plasma have been identified as localized ‘‘hot spots’’ for charge-exchange power loss in some cases. In addition, the total charge exchange power loss is found to be in order-of-magnitude agreement with predictions from a zero-dimensional (0-D) model and can account for the bulk of the edge-dominated spheromak power loss.

The energy distribution of neutral particles is detected from spheromak plasmas by a time of flight neutral atom spectrometer. These particles originate in charge exchange interactions within the bulk plasma and carry the temperature of the majority ion component. This is the first direct measurement of temperatures of the main ion species in spheromaks. The data are found to be in the range of 500 eV during the sustainment and late decay phases and are in agreement with impurity Doppler temperatures for species expected to be localized to the plasma centre.

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High current densities ( 106-107 A/cm2) produce magnetic fields which can induce antiparallel magnetic alignment in large (16 pm and 8 pm) NiFe/Ag thin film multilayer devices. We induce GMR in unannealed devices which normally do not display GMR. We find multiple peaks in the magnetoresistance curves of annealed and unannealed devices. Analysis of the positions and shapes of these magnetoresistance peaks provides a new set of tools for determining the micromagnetic structure of the multilayers. Our magneto-opticaI Kerr effect data and low frequency noise data correlate with the magnetoresistance peaks and may yield further information about layer-layer interactions and domain structure.