Speaker
Description
Pulsars provide a sensitive probe of heliospheric plasma through propagation-induced variations in dispersion measure (DM) (which measures the total electron column density) and scattering (which measures the scale of density perturbations perpendicular to the line of sight), particularly during solar conjunction. The Canadian Hydrogen Intensity Mapping Experiment (CHIME), together with its outrigger stations across North America, enables high-cadence, multi-baseline radio observations that are well suited for investigating these propagation effects.
We analyze CHIME observations of the Crab Pulsar (PSR B0531+21) obtained during solar conjunction. Multi-station correlation analyses are used to characterize scattering signatures while the high sensitivity of the main station provides DM measurements. Preliminary results show enhanced dispersion measure and scattering during close solar approaches, consistent with increased plasma density and turbulence along the line of sight.
We compare the measured DM variations with DM predictions derived from both an idealized Parker solar-wind density model and Parker Solar Probe (PSP) SWEAP observations. Electron density profiles are estimated from PSP measurements within time windows centered on each pulsar observation and mapped into the Earth–Crab Line of Sight (LOS) geometry to predict the corresponding solar-wind DM contribution. To better isolate the heliospheric component, we model the slowly varying interstellar DM contribution as a time-dependent trend rather than assuming a constant background.
Together, these analyses demonstrate the potential of combining multi-station pulsar observations, theoretical solar-wind models, and in-situ spacecraft measurements to quantitatively investigate the density structure and turbulence of the inner heliosphere.
| What area of study best describes your talk? | Analysis |
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