152 citations · 726 across the 17 of their papers we have counts for
17 papers
Photospheric Velocities Measured at Mt. Wilson Show Zonal and Sectoral Flows Compose the Torsional Oscillations
Roger K. Ulrich, Tham Tran, John Boyden
The methods for reducing the observations from the 150-foot Tower Telescope on Mt.~Wilson are reviewed and a new method for determining the North/South (sectoral) and the East/West…
Magnetograph Saturation and the Open Flux Problem
Y. -M. Wang, R. K. Ulrich, J. W. Harvey
Extrapolations of line-of-sight photospheric field measurements predict radial interplanetary magnetic field (IMF) strengths that are factors of ~2--4 too low. To address this "ope…
Reconstructing solar magnetic fields from historical observations V. Sunspot magnetic field measurements at Mount Wilson Observatory
Alexei A. Pevtsov, Kseniya A. Tlatova, Alexander A. Pevtsov +7
Context. Systematic observations of magnetic field strength and polarity in sunspots began at Mount Wilson Observatory (MWO), USA in early 1917. Except for a few brief interruption…
Solar Sources of Interplanetary Magnetic Clouds Leading to Helicity Prediction
Roger K. Ulrich, Pete Riley, T. Tran
This study identifies the solar origins of magnetic clouds that are observed at 1 AU and predicts the helical handedness of these clouds from the solar surface magnetic fields. We…
Asymptotic g modes: Evidence for a rapid rotation of the solar core
E. Fossat, P. Boumier, T. Corbard +11
We present the identification of very low frequency g modes in the asymptotic regime and two important parameters that have long been waited for: the core rotation rate, and the as…
Generation of a North/South Magnetic Field Component from Variations in the Photospheric Magnetic Field
Roger K. Ulrich, Tham Tran
We address the problem of calculating the transverse magnetic field in the solar wind outside of the hypothetical sphere called the source surface where the solar wind originates.…