This paper reports the results of a survey of Doppler shift oscillations measured during solar flares in emission lines of S XV and Ca XIX with the Bragg Crystal Spectrometer (BCS) on Yohkoh. Data from 20 flares that show oscillatory behavior in the measured Doppler shifts have been fitted to determine the properties of the oscillations. Results from both BCS channels show average oscillation p...

We report the experimental observation of an inverse Doppler shift from the motion of an ordinary solid object. The experiment used left-handed, or backward, spin waves in a magnetic thin film. As a pick-up antenna was moved toward the spin wave source, the measured frequency decreased. In contrast, an increase would be expected in everyday experience as the observer approaches the source. The ...

llstimation This paper presents a new range and Doppler centroid estimation algorithm for a ScanSAR system. Its accurate range and Doppler centroid estimates lead to refined radar pointing angles, which enables the ScanSAR imagery meeting its radiometric requirements. This algorithm attains an accuracy equal to the Cramer Rae's lower bound for both the homogeneous and quasi-homogeneous targets....

We show that the use of Doppler shifts of Zeeman sensitive spectral lines to observe waves in sunspots is subject to measurement specific phase shifts arising from, (i) altered height range of spectral line formation and the propagating character of p mode waves in penumbrae, and (ii) Zeeman broadening and splitting. We also show that these phase shifts depend on wave frequencies, strengths and...

This paper presents signal properties of spaceborne, strip-map SAR for very large squint angles. Doppler centroid, azimuth bandwidth, and exposure time are derived in terms of the platform attitude and elevation angle. This allows a description of the Doppler centroid variation with range and terrain height, and explains a possible range dependence of azimuth bandwidth at high squint. The yaw a...

We analyze the effect of weak field gravitational waves on the timing of pulsars, with particular attention to gauge invariance, that is, to the effects that are independent of the choice of coordinates. We find: (i) the Doppler shift cannot be separated into gauge invariant gravitational wave and kinetic contributions; (ii) a gauge invariant separation can be made for the time derivative of th...

This paper is devoted to the asymptotic analysis of a coupled model arising in radiative transfer. The model consists of a kinetic equation satisfied by the specific intensity of radiation coupled to a diffusion equation satisfied by the material temperature. The interaction terms take into account both scattering and absorption/emission phenomena, as well as Doppler corrections. Two asymptotic...

Optical Doppler shift demonstration experiments are not a simple task since the light source cannot usually be moved in a sufficiently smooth and uniform manner to keep the level of noise well below of that of the signal. For that reason most demonstration experiments are usually performed with sound or with microwaves. Previous works have been reported using a moving mirror in order to produce...

Damped Doppler shift oscillations have been observed in emission lines from ions formed at flare temperatures with the Solar Ultraviolet Measurements of Emitted Radiation spectrometer on the Solar and Heliospheric Observatory and with the Bragg Crystal Spectrometer on Yohkoh. This Letter reports the detection of low-amplitude damped oscillations in coronal emission lines formed at much lower te...