Energetic Ion Moments and Polytropic Index in Saturn’s Magnetosphere using Cassini/MIMI Measurements: A Simple Model Based on κ‐Distribution Functions

Moments of the charged particle distribution function provide a compact way of studying the transport, acceleration, and interactions of plasma and energetic particles in the magnetosphere. We employ κ‐distributions to describe the energy spectra of H+ and O+, based on >20 keV measurements by the three detectors of Cassini’s Magnetospheric Imaging Instrument, covering the time period from DOY 183/2004 to 016/2016, 5 < L < 20. From the analytical spectra we calculate the equatorial distributions of energetic ion moments inside Saturn’s magnetosphere and then focus on the distributions of the characteristic energy (Ec=IE/In), temperature, and κ‐index of these ions. A semiempirical model is utilized to simulate the equatorial ion moments in both local time and L‐shell, allowing the derivation of the polytropic index (Γ) for both H+ and O+. Primary results are as follows: (a) The ∼9 < L < 20 region corresponds to a local equatorial acceleration region, where subadiabatic transport of H+ (Γ∼1.25) and quasi‐isothermal behavior of O+ (Γ∼0.95) dominate the ion energetics; (b) energetic ions are heavily depleted in the inner magnetospheric regions, and their behavior appears to be quasi‐isothermal (Γ<1); (c) the (quasi‐) periodic energetic ion injections in the outer parts of Saturn’s magnetosphere (especially beyond 17–18 RS) produce durable signatures in the energetic ion moments; (d) the plasma sheet does not seem to have a ground thermodynamic state, but the extended neutral gas distribution at Saturn provides an effective cooling mechanism that does not allow the plasma sheet to behave adiabatically.Key PointsDerivation of energetic ion moments, κ‐index, characteristic energy, temperature, and polytropic index in Saturn’s magnetospherePresentation of a semiempirical analytical model for the 20 keV energetic ion Pressure, density, and temperatureThe neutral gas at Saturn provides an effective cooling mechanism and does not allow the plasma sheet to behave adiabaticallyPeer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/146558/1/jgra54546.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/146558/2/jgra54546_am.pd

Ultraviolet and Visible Imaging and Spectrographic Imaging (UVISI) Data Processing Center (DPC)

International Telemetering Conference Proceedings / October 28-31, 1996 / Town and Country Hotel and Convention Center, San Diego, CaliforniaThe nine sensors and one image processor of the Ultraviolet and Visible Imaging and Spectrographic Imaging (UVISI) instrument aboard the Midcourse Space Experiment (MSX) satellite can potentially generate up to three gigabytes of data of data per day. The UVISI Data Processing Center (DPC) must execute a multitude of complex processing functions in a 24-hour operational window, verify the UVISI data and also provide a compact, quantified record of the verification. The Center additionally must support higher-level data analysis functions. Data processing functions are divided into pipeline processing and data conversion processing. Pipeline processing, which consists of the main pipeline process, Pipeline, and several auxiliary processes is responsible for generating Data Quality Indices (DQI) that summarize sensor performance and Data Measurement Indices (DMI) that summarize sensor measurements. Both sets of indices provide scientists and engineers with a compact, easily-reviewed record of instrument performance. The conversion process, Convert, supports data analysis by converting raw telemetry into scientific/engineering units. On a pixel-by-pixel basis, Convert provides functions for dark-correction, flat-fielding, gain and gate adjustment, non-linearity correction, and count-to-photon conversion. Operating in conjunction with Convert, a pointing utility, Point, is used to determine the locations of selected objects in inertial space. The accomplishment of these myriad tasks relies on a state-of-the-art computer network using multiple workstations. Normal DPC operations are fully automated but remain flexible enough to allow prompt intervention by the UVISI Performance Assessment Team (PAT).International Foundation for TelemeteringProceedings from the International Telemetering Conference are made available by the International Foundation for Telemetering and the University of Arizona Libraries. Visit http://www.telemetry.org/index.php/contact-us if you have questions about items in this collection