Search Publications
Solar maximum low-energy particle observations at heliographic latitudes above 75 degrees
Lario, D.; Reisenfeld, D. B.; Roelof, E. C. +1 more
We present a preliminary analysis of low-energy particle observations by the Ulysses and ACE spacecraft during the time intervals that Ulysses spent at heliographic latitudes above 75 degrees during its solar maximum orbit. The most southerly and northerly latitudes (80.2°) were reached by Ulysses in November 2000 and October 2001, respectively. T…
Particle drift effects on cosmic ray modulation during solar maximum
Ferreira, S. E. S.; Potgieter, M. S.; Heber, B.
A fully time-dependent cosmic ray modulation model based on the numerical solution of Parker's transport equation is used to study the amount of particle drifts needed to explain the observed 1.2 GV electron to Helium ratio at Earth and the 2.5 GV electron to proton ratio (e/p) observed by the KET instrument on the Ulysses spacecraft. The model su…
Modulation of galactic cosmic rays at solar maximum: Observations
Zhang, Ming
The spectra of galactic cosmic rays observed anywhere inside the heliosphere are modulated by the sun because the charged particles must fight their ways inward against the radially expanding solar wind. In the past half a century, galactic cosmic ray fluxes at Earth were continuously monitored by neutron monitors on the ground and instruments on …
Wind-Ulysses in-situ thermal noise measurements of solar wind electron density and core temperature at solar maximum and minimum
Maksimovic, M.; Issautier, K.; Hoang, S. +2 more
The radio receivers on the Wind and Ulysses spacecraft in the solar wind continuously record spectra of the quasi-thermal plasma noise near the electron plasma frequency, from which the electron density and core temperature can be determined using the method of quasi-thermal noise spectroscopy. Such in-situ thermal noise measurements were obtained…
First results of a new 3-D model of the time-dependent modulation of electrons in the heliosphere
Fichtner, H.; Ferreira, S. E. S.; Potgieter, M. S. +2 more
We employ our recently developed ansatz for the time-dependent 3-D modelling of Jovian and galactic electrons in the inner heliosphere. The main goal of the study is to check whether the form of the diffusion tensofi as determined recently by Ferreira et al. (2001a,b) with an extended parameter study of the steady state is also useful for comparis…
Transport of a few-MEV jovian and galactic electrons at solar maximum
Ferreira, S. E. S.; Potgieter, M. S.; Heber, B. +2 more
The heliospheric modulation of galactic and jovian electrons is studied using a three-dimensional, steady-state model based on Parker's transport equation including the jovian source. The model is developed to study both jovian and galactic electrons. It is illustrated how the electron intensity-time profile along the Ulysses trajectory is effecte…
Distinct shock acceleration processes — Evaluation of the magnetic trap dimensions formed upstream of an interplanetary shock using measurements of the ulysses spacecraft
Sarris, E. T.; Anagnostopoulos, G. C.; Marhavilas, P. K. +1 more
We analyze the acceleration signatures of energetic ions (E > 50 keV) and electrons (E > 30 keV) being observed on day 256 of the year 1992 UT, in the vicinity of the surface of a fast-mode quasi-perpendicular interplanetary hydromagnetic shock, using fine time resolution measurements by the HI-SCALE instrument onboard the Ulysses spacecraft…
Heliospheric Langmuir wave observations from the Ulysses spacecraft
McComas, D. J.; Lin, Naiguo; MacDowall, R. J.
Langmuir waves are electrostatic plasma oscillations produced by unstable electron beams in the solar wind and elsewhere. Typical electron sources are solar flares, shocks, and magnetic holes. In this paper, we present an overview of the Langmuir waves observed by Ulysses during both its solar minimum and solar maximum orbits. Langmuir waves in ma…
Quiet time MEV electron increases at solar maximum: Ulysses cospin/ket observations
Fichtner, H.; Kunow, H.; Wibberenz, G. +10 more
The Ulysses trajectory provides a unique opportunity to study the propagation of MeV electrons in a wide range of heliographic latitudes and during varying conditions in the inner heliosphere. In recent papers we reported Ulysses Kiel Electron Telescope (KET) observations from the Ulysses launch up to the end of the second fast latitude scan in la…
The dynamic 3D heliosphere: Implications for and new sources of its energetic particles
McComas, D. J.; Schwadron, N. A.
In recent years, two important aspects of heliospheric physics have emerged: (1) the intrinsic dynamism of the Sun's open magnetic flux and its vast importance for energetic particle propagation and acceleration; and (2) the importance of heliospheric grain populations for the production of energetic particles and anomalous cosmic rays. These new …