Stephen M. White

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This paper deals with a feasibility study for a System-onChip (SoC) mm-wave radiometer devoted to space-based observation of solar flares and operating in the Ka-band. The radiometer has been designed in 250 nm SiGe BiCMOS process. The circuit integrates a three stages differential LNA with 37.2 dB gain and 4.8 dB noise figure at 36.8 GHz and a differential(More)
The measurement of magnetic field strengths in the solar corona using radio observations is reviewed. This is a well established technique that exploits the fact that the electron gyrofrequency for typical coronal magnetic field strengths (100–2000 Gauss) lies in the radio frequency range. Opacity from the resulting gyroresonance emission from hot plasma(More)
We analyze a small are using imaging data at millimeter, microwave and soft X{ray wavelengths, and microwave and hard X{ray spectral observations. The remarkable aspect of this are is evidence for the presence of MeV{energy electrons, which are responsible for the nonthermal millimeter emission, at a time when no hard X{rays from lower{energy electrons are(More)
In this paper we seek a self{consistent model for three strong limb ares observed at 17 and 34 GHz by the Nobeyama radioheliograph (NoRH) and also in soft X{rays and hard X{rays by the SXT and HXT instruments on board Yohkoh. Additional radio spectral data were provided by the Nobeyama polarimeter. The SXT images showed that the are geometry is simple with(More)
The temporal relationship between coronal mass ejections (CMEs) and associated solar Ñares is of great importance to understanding the origin of CMEs, but it has been difficult to study owing to the nature of CME detection. In this paper, we investigate this issue using the Large Angle and Spectrometric Coronagraph and the EUV Imaging Telescope observations(More)
A radio frequency interference (RFI) excision algorithm based on spectral domain statistics is proposed and implemented in software. The algorithm requires the use of two memory buffers, S1 and S2, in which the first two powers of M power spectral density (PSD) estimates, obtained via Fast Fourier Transform (FFT), are accumulated and used to form a Spectral(More)
We compare microwave images of a solar active region with state-of-the-art fully-nonlinear force-free extrapolations of the photospheric elds in order to study the link between coronal currents and heating of the corona. This extrapolation fully takes into account the nonuni-form distribution of electric currents observed in the photosphere and its role in(More)
As models for the physical properties of the corona above solar active regions grow more sophisticated, we will require better means for testing them. In this paper we discuss and apply such a test to a magnetic eld model for an active region. This test is based on the expectation that the temperatures at diierent points on a given magnetic eld line should(More)