Search

We use wavelet transforms to study the characteristic time scales of chromospheric oscillation "wave packets" that are observed in Transition Region and Coronal Explorer (TRACE) ultraviolet continuum image time series. Using several data sets, we investigate the statistical, spatial, and temporal intermittence of the number, duration, mean frequency, and delay ("wait time") between wave packets in the time series data. Further, we demonstrate that these characteristic values are consistent with newly developed pictures of the wave-mode suppression and conversion by the chromospheric magnetic "canopy." We propose that wavelet analysis may be fruitfully used in diagnosing the structure of the chromosphere and in identifying chromospheric oscillation wave packets temporally and spatially with their photospheric sources.

Accurate high resolution UV/VUV atomic data are required for interpretation of astrophysical spectra acquired by modern spectrographs on astronomical telescopes. Atomic spectroscopy studies by high resolution Fourier Transform spectrometry at Imperial College are described.

Accurate new high-resolution UV and VUV atomic and molecular data for astrophysics and atmospheric physics are needed. Extension of Fourier transform spectroscopy into the VUV at Imperial College is outlined, and laboratory spectroscopy applications described.