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Scalar helium magnetometer observations at Cassini Earth swing-by
Dougherty, Michele K.; Russell, Christopher T.; Smith, Edward J. +1 more
When the Cassini spacecraft passed by Earth en route to the outer solar system, the magnetic field magnitude was measured with extremely high accuracy by the onboard helium magnetometer operating in the scalar mode. Magnitude measurements of the near-equatorial field were obtained inbound from 4 to 1.17RE at local times from postnoon to…
Scales of heliospheric current sheet coherence between 1 and 5 AU
Crooker, N. U.; Smith, E. J.; De Keyser, J. +4 more
The structure of the heliospheric current sheet (HCS) at Ulysses and at Wind is compared during the period of near-radial alignment in 1998. Electron heat flux and magnetic field data are used to determine true magnetic field polarity. During the solar rotation period surrounding alignment there was considerable disagreement between the HCS crossi…
Background reduction for quiet time particle fluxes aboard the Solar and Heliospheric Observatory
Valtonen, E.; Torsti, J.; Kunow, H. +2 more
Two versions of a method are presented to determine the background of energetic particle telescopes during low-flux periods at low energies. Traditional procedures first evaluate pulse heights of particle sensors working in coincidence then select certain areas of the ΔE/Δx versus E plane, where E is energy, and finally, accept all events falling …
Energetic particle measurements during the earth swing-by of the Cassini spacecraft in August 1999
Livi, S.; Krupp, N.; Woch, J. +3 more
We report on energetic particle measurements from the Low-Energy Magnetospheric Measurement System (LEMMS) aboard the Cassini spacecraft during the Earth swing-by maneuver in August 1999. LEMMS is capable of identifying the energy and incidence direction of energetic ions and electrons with energies of a few tens of keV to several tens of MeV. Cas…
Ulysses observations of magnetohydrodynamic turbulence in corotating interaction regions
Cargill, P. J.; Gulamali, M. Y.
During its mission around the poles of the Sun, the Ulysses spacecraft encountered a number of well-developed corotating interaction regions (CIRs) at midlatitudes. In this paper we discuss the character of magnetohydrodynamic (MHD) turbulence within defined regions of these CIRs. We examine magnetic field power spectra at a fixed wave number, and…
Cassini radio detection and ranging (RADAR): Earth and venus observations
Lorenz, R. D.; West, R. D.; Janssen, M. A. +11 more
The Cassini Radio Detection and Ranging (RADAR) was operated in scatterometric and radiometric modes during the Venus 1 and Earth swingbys to verify its functionality. At Venus, only the thermal emission from the thick absorbing atmosphere was detected. At Earth both the radar echo and the microwave emission from the surface were detected and reve…
Contribution of the Solar Constant (SOLCON) program to the long-term total solar irradiance observations
Dewitte, S.; Helizon, R.; Wilson, R. S.
On long timescales the variation of the total solar irradiance (TSI) received by the Earth is believed to be one of the climate change drivers. Therefore accurate and time-stable measurements of the total solar irradiance are necessary. The Solar Constant (SOLCON) instrument made TSI measurements in April 1992 and during the International Extreme …
Coherence of charged particle oscillations in the heliosphere (f~5µHz): Implications for a solar modulation source
Kunow, H.; Lanzerotti, L. J.; Gold, R. E. +3 more
Time series analysis of low-energy electron and high-energy proton cosmic ray fluxes, both measured on the Ulysses spacecraft, shows that they are quite coherent in some frequency bands in the energy range 0-6 µHz, especially near 5 µHz. Interplanetary particle fluxes with very different kinematic properties (e.g., gyrofrequencies) are…
Cassini plasma spectrometer observations of bidirectional lobe electrons during the Earth flyby, August 18, 1999
Coates, A. J.; Linder, D. R.; Dougherty, M. K. +4 more
Unlike previous missions to the magnetotail (IMP 6, ISEE 1, ISEE 3, and Geotail), which effectively made observations in the lobe at a single downtail distance, the Cassini Earth swingby allowed, for the first time, near-continuous observations covering a range of downtail distances. Bidirectional electrons are found in the northern lobe, consiste…
Fragmented structure of interplanetary type II bursts
MacDowall, R. J.; Thejappa, G.
We present the Ulysses observations of a highly fragmented interplanetary type II burst and an associated pair of forward shocks. We argue that the coupling of Langmuir waves excited by one of these shocks with escaping radiation at the sharp density gradient associated with the companion shock is responsible for the clumpiness of the type II even…