3-D reconstructions of the early-November 2004 CDAW geomagnetic storms: analysis of Ooty IPS speed and density data

Abstract

Abstract.Interplanetary scintillation (IPS) remote-sensing observations provide a view of the solar wind covering a wide range of heliographic latitudes and heliocentric distances from the Sun between ∼0.1 AU and 3.0 AU. Such observations are used to study the development of solar coronal transients and the solar wind while propagating out through interplanetary space. They can also be used to measure the inner-heliospheric response to the passage of coronal mass ejections (CMEs) and co-rotating heliospheric structures. IPS observations can, in general, provide a speed estimate of the heliospheric material crossing the observing line of site; some radio antennas/arrays can also provide a radio scintillation level. We use a three-dimensional (3-D) reconstruction technique which obtains perspective views from outward-flowing solar wind and co-rotating structure as observed from Earth by iteratively fitting a kinematic solar wind model to these data. Using this 3-D modelling technique, we are able to reconstruct the velocity and density of CMEs as they travel through interplanetary space. For the time-dependent model used here with IPS data taken from the Ootacamund (Ooty) Radio Telescope (ORT) in India, the digital resolution of the tomography is 10 • by 10 • in both latitude and longitude with a half-day time cadence. Typically however, the resolutions range from 10 • to 20 • in latitude and longitude, with a half-to one-day time cadence for IPS data dependant upon how much data are used as input to the tomography. We compare reconstructed structures during early-November 2004 with in-situ measurements from the Wind spacecraft orbiting the Sun-Earth L 1 -Point to valCorrespondence to: M. M. Bisi (mmbisi@ucsd.edu) idate the 3-D tomographic reconstruction results and comment on how these improve upon prior reconstructions.

Inclusion of Real-Time In-Situ Measurements into the UCSD Time-Dependent Tomography and Its Use as a Forecast Algorithm

“…For comparison with the in-situ data at resolutions commensurate with the 3D reconstructions, the ACE data have been "boxcar averaged" using a 3/4-day-interval filter. The correlation with in-situ density without the inclusion of in-situ measurements during this particular CR is relatively poor; often higher correlations for specific periods near CMEs and/or other whole CRs are reported (e.g., Jackson et al, 2003;Dunn et al, 2005;Bisi et al, 2009aBisi et al, , 2009b using STELab and other data sets in the reconstructions. As expected, there is a higher correlation (from 0.243 to 0.533) with the inclusion of the ACE in-situ density measurements for our reconstructions (Figure 4c, 4d), and this is a significant improvement in the results shown in this example.…”

“…Over the years a Computer Assisted Tomography (CAT) program has been developed (Jackson et al, , 2003(Jackson et al, , 2010dKojima et al, 1998;Jackson, Hick, and Buffington, 2002;Hick and Jackson, 2004;Jackson and Hick, 2005) that iteratively fits remotely-sensed observations to a kinematic solar-wind model. Other articles detail how the time-dependent tomographic analyses can be used to map to velocities and densities to near Earth (e.g., Jackson et al, 2006Jackson et al, , 2008Jackson et al, , 2010cBisi et al, 2007Bisi et al, , 2009aBisi et al, , 2010a, at Mars , and at the Solar TErrestrial RElations Observatory (STEREO) spacecraft (Kaiser et al, 2008). See Bisi et al (2009b) and Jackson et al (2011), for the STEREO analyses.…”

A Study of the 3-D Reconstruction of Heliospheric Vector Magnetic Fields From Faraday-Rotation Inversion

“…Current efforts are underway to determine the validity of the Ooty data during the current period of solar minimum activity. So far these analyses have not been very successful even though periods during solar maximum have been reconstructed well (Bisi et al, 2008a;2009b) (Figure 3 and Figure 4 are from these articles.). The SMEI instrument has also provided extremely fine measurements of archival heliospheric density data for select intervals (Jackson et al, 2008a, Bisi et al, 2008b, and in the latter article these analyses were used to drive a time-dependent 3-D MHD model that compares successfully with the kinematic model usually used as a kernel in the UCSD 3-D reconstruction program.…”

“…The IPS density volumes (either from STELab or density fall-off scaling is used to normalize structures at different radii. Density contours to the left of each image are scaled to 1AU (from Bisi et al, 2009b). UCSD-2005-4253 6 from other IPS radio sites) will allow a test of the feasibility of FR magnetic field reconstruction when ground-based FR observations become available, and if SMEI data are available at the same time, these data can be used to determine an even better density proxy for magnetic field reconstruction results.…”

A Heliospheric Imager for Deep Space: Lessons Learned from Helios, SMEI, and STEREO

“…IPS observations taken using the Cambridge IPS array in the UK (Houminer, 1971), show structures that can be classified as either corotating or detached from the Sun (Gapper et al, 1982;Hewish and Bravo, 1986;Behannon, Burlaga, and Hewish, 1991). More recently, IPS data used in conjunction with tomographic threedimensional (3D) reconstruction techniques have shown the global shapes of heliospheric density and velocity structures including corotating regions and coronal mass ejections (CMEs) or their interplanetary counterparts (ICMEs) in the solar wind (see, e.g., Jackson et al, 1998;Kojima et al, 1998;Asai et al, 1998;Jackson, Hick, and Buffington, 2002;Jackson et al, 2003;Jackson and Hick, 2005;Tokumaru et al, 2007;Tokumaru, Kojima, and Fujiki, 2010;Bisi et al, 2007Bisi et al, , 2008aBisi et al, , 2008bBisi et al, , 2009aBisi et al, , 2009bJackson et al, 2008aJackson et al, , 2008bJackson et al, , 2009Jackson et al, , 2010. These tomographic analyses match in-situ spacecraft measurements from near-Earth spacecraft fairly well.…”