Search Publications
A Comprehensive View of the 2006 December 13 CME: From the Sun to Interplanetary Space
Liu, Y.; Sauvaud, J. -A.; Luhmann, J. G. +7 more
The biggest halo coronal mass ejection (CME) since the Halloween storm in 2003, which occurred on 2006 December 13, is studied in terms of its solar source and heliospheric consequences. The CME was accompanied by an X3.4 flare, EUV dimmings, and coronal waves. It generated significant space weather effects such as an interplanetary shock, radio b…
Identifying Current-Sheet-like Structures in the Solar Wind
Li, G.
In past years, measurements of the solar wind plasma have advanced our understanding of MHD turbulence tremendously. At small scales, the solar wind is believed to be ve`xry multifractal with nonlinear interactions causing an intermittent energy dissipation, leading to possible current-sheet structures. In this Letter, we propose a systematic data…
Effects of Scattering on Radio Emission from the Quiet Sun at Low Frequencies
MacDowall, R. J.; Thejappa, G.
The observations of the quiet Sun at meter and decameter wavelengths show that its brightness temperatures can be ~1 order of magnitude lower than the expected values of 106 K and the apparent diameters can be very large. We examine whether this unusual behavior is due to refraction in the smoothly varying coronal plasma and scattering …
The Solar Wind Power from Magnetic Flux
McComas, D. J.; Schwadron, N. A.
Observations of the fast, high-latitude solar wind throughout Ulysses' three orbits show that solar wind power correlates remarkably well with the Sun's total open magnetic flux. These observations support a recent model of the solar wind energy and particle sources, where magnetic flux emergence naturally leads to an energy flux proportional to t…
Latitudinal Gradients of Galactic Cosmic Rays during the 2007 Solar Minimum
Mewaldt, R. A.; Gómez-Herrero, R.; Ferreira, S. E. S. +6 more
Ulysses, launched in 1990 October in the maximum phase of solar cycle 22, completed its third out-of-ecliptic orbit in 2008 February. This provides a unique opportunity to study the propagation of cosmic rays over a wide range of heliographic latitudes during different levels of solar activity and different polarities in the inner heliosphere. Com…
The Signature of Evolving Turbulence in Quiet Solar Wind as Seen by Ulysses
Chapman, S. C.; Nicol, R. M.; Dendy, R. O.
Solar wind fluctuations, such as magnetic field or velocity, show power-law power spectra suggestive both of an inertial range of intermittent turbulence (with ~-5/3 exponent), and at lower frequencies, of fluctuations of coronal origin (with ~-1 exponent). The Ulysses spacecraft spent many months in the quiet fast solar wind above the Sun's polar…
Comparison of Heliospheric In Situ Data with the Quasi-steady Solar Wind Models
Riley, P.; Lepri, S. T.; Antiochos, S. K. +2 more
The standard theory for the solar-heliospheric magnetic field is the so-called quasi-steady model in which the field is determined by the observed magnetic flux at the photosphere and the balance between magnetic and plasma forces in the corona. In this model, the solar magnetic flux that opens to the heliosphere can increase or decrease as the ph…
Cosmic Ray Transport and Production in the Galaxy: A Stochastic Propagation Simulation Approach
Zhang, Ming; Connell, J. J.; Rassoul, Hamid +1 more
Galactic cosmic-ray composition reflects the effects of nuclear interactions during propagation through the interstellar medium. In order to use measurements to determine the source of cosmic rays, one needs a model to deconvolute the propagation effect. This paper presents a new numerical method to solve cosmic-ray diffusive transport equations w…
Ultrarelativistic Electrons in Jupiter's Inner Magnetosphere: First Observation of Angular Distributions in the 2.5 to 6 RJ Region
Armstrong, Thomas P.; Taherion, Saeed; Garrett, Henry B.
Jupiter has been recognized as a probable location of magnetically trapped ultrarelativistic electrons since its discovery as a source of polarized decimeter radio waves. A series of spacecraft (Pioneers 10 and 11, Voyagers 1 and 2, Ulysses, Cassini, and New Horizons) have flown by and orbited Jupiter with the goal of observing the trapped radiati…
Elemental Abundances of Energetic Particles within Magnetic Clouds Detected by Ulysses
Fränz, Markus; Krupp, Norbert; Woch, Joachim +1 more
The study of particles from the solar wind thermal population up to higher near-relativistic energies provides a tool to analyze and characterize the internal structure of magnetic clouds (MCs). In this work, we analyze the elemental composition of energetic particles at ~1 MeV nucleon-1. Statistically, using a data set of 40 MCs, we fi…