Carmel Research Center Inc.

Santa Monica, CA, United States

Carmel Research Center Inc.

Santa Monica, CA, United States
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Intriligator D.S.,Carmel Research Center Inc. | Sun W.,Carmel Research Center Inc. | Sun W.,University of Alaska Fairbanks | Detman T.,Carmel Research Center Inc. | And 8 more authors.
Journal of Physics: Conference Series | Year: 2016

The Sun has been observed for many years to be a dynamic influence in the heliosphere, and as the Voyager missions have continued long after achieving their original goals of observing the major planets they have provided the first in situ observations of the effects of solar activity in the heliosheath (HS), and the nearest portions of the local Interstellar Medium (LISM). Comparing these observations with models provides key insights. We employ two three-dimensional (3D) time-dependent models that simulate the propagation of shocks, other specific features, and the background solar wind throughout the heliosphere, starting with the solar background and solar event boundary conditions near the Sun at 2.5 Rs. The Hybrid Heliospheric Modeling System with Pickup Protons (HHMS-PI) is a 3D time- dependent Magnetohydrodynamic (MHD) simulation. HAFSS (HAF Solar Surface) is a 3D time-dependent kinematic simulation. Comparing our models with the observations indicates that solar effects are seen in the heliosphere, the HS, and the LISM in in-situ spacecraft measurements of plasma, magnetic field, energetic particles, cosmic rays, and plasma waves. There is quantitative agreement (at ACE, Ulysses, VI, V2) with data (e.g., solar wind, IMF, Ulysses SWICS pickup protons (PUPs)). Propagating shocks are slowed due to PUPs. The 3D locations of solar events and of various spacecraft are key to understanding the 3D propagation and timing of shocks, other specific features, and gradients throughout the heliosphere, HS, and LISM. © Published under licence by IOP Publishing Ltd.


Intriligator D.S.,Carmel Research Center Inc. | Intriligator J.,Bangor University | Miller W.D.,Carmel Research Center Inc. | Webber W.R.,New Mexico State University | Decker R.B.,Johns Hopkins University
Journal of Geophysical Research: Space Physics | Year: 2010

We have found in the Voyager 2 (V2) plasma science data in the heliosheath (HS) near the termination shock (TS) high-energy ions (HEIs) in addition to the bulk plasma convective flow ions. The HEI detections temporally coincide with increased V2 plasma wave subsystem (PWS) activity in "event A" of Gurnett and Kurth (2008). Maxwellian fits to HEI detections indicate the HEIs are moving radially anti-Sunward with a proton speed of 600 km/s, a density of 10-4 cm-3, and a thermal speed of 10 km/s. The heliosheath bulk convective protons have a speed of 204 km/s, a density of 0.0029 cm -3, and a thermal speed of 26.7 km/s. The HEI flux and ram pressure are approximately 10% and 30% of those of the bulk HS flow. Since the HEI speed is both close to twice the solar wind speed and independent of the heliosheath bulk plasma speed, the HEIs may be detections of pickup protons formed in the solar wind and convected through the TS. The HEIs also are reminiscent of the pickup protons upstream of the Mars bow shock where their energy also was independent of the bulk plasma speed and attributed to multiple reflections off the Mars bow shock. Gurnett and Kurth's (2008) event A enhanced PWS activity may be generated by a two-stream instability from the interaction of these HEIs with the heliosheath bulk plasma ions. We present our findings, discuss their implications, and also present alternative interpretations. Copyright 2010 by the American Geophysical Union.


Intriligator D.S.,Carmel Research Center Inc. | Detman T.,Carmel Research Center Inc. | Gloecker G.,University of Michigan | Gloeckler C.,University of Michigan | And 5 more authors.
Journal of Geophysical Research: Space Physics | Year: 2012

We report the first comparisons of pickup proton simulation results with in situ measurements of pickup protons obtained by the SWICS instrument on Ulysses. Simulations were run using the three dimensional (3D) time-dependent Hybrid Heliospheric Modeling System with Pickup Protons (HHMS-PI). HHMS-PI is an MHD solar wind model, expanded to include the basic physics of pickup protons from neutral hydrogen that drifts into the heliosphere from the local interstellar medium. We use the same model and input data developed by Detman et al. (2011) to now investigate the pickup protons. The simulated interval of 82 days in 2003-2004, includes both quiet solar wind (SW) and also the October-November 2003 solar events (the "Halloween 2003" solar storms). The HHMS-PI pickup proton simulations generally agree with the SWICS measurements and the HHMS-PI simulated solar wind generally agrees with SWOOPS (also on Ulysses) measurements. Many specific features in the observations are well represented by the model. We simulated twenty specific solar events associated with the Halloween 2003 storm. We give the specific values of the solar input parameters for the HHMS-PI simulations that provide the best combined agreement in the times of arrival of the solar-generated shocks at both ACE and Ulysses. We show graphical comparisons of simulated and observed parameters, and we give quantitative measures of the agreement of simulated with observed parameters. We suggest that some of the variations in the pickup proton density during the Halloween 2003 solar events may be attributed to depletion of the inflowing local interstellar medium (LISM) neutral hydrogen (H) caused by its increased conversion to pickup protons in the immediately preceding shock. © 2012. American Geophysical Union. All Rights Reserved.

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