Extend this unit's standoff-distance and DPS ring-current tools to new wind conditions and sensitivity checks.
Compute the magnetopause standoff distance for the fast (coronal-hole) solar wind condition in this unit's data table, and state whether it is closer to the quiet-wind or the storm-sheath standoff distance computed in the lab.
Using the DPS relation's linear dependence on Dst, compute the ring-current energy for a hypothetical storm with Dst=-284 nT (exactly double the real 2017 storm's Dst magnitude), and confirm it is exactly double the 2017 storm's ring-current energy computed in the lab.
The reference energy E0=B0^2 R_E^3/(6 mu0) depends on Earth's equatorial field strength B0. Recompute E0 using a 5% larger B0 (representing the slow secular change in Earth's field over centuries) and compute the percent change in E0. Discuss whether this effect is likely to matter for comparing Dst-derived ring-current energies across a 165-year gap (1859 to 2024).
Using the pressure factor computed in the lab (needed to compress the magnetopause to geosynchronous orbit), and the real quiet-wind dynamic pressure, compute the actual solar wind speed (holding density fixed at the quiet-wind value) that would be required to reach this pressure factor.
Submit a complete derivation with equations, units, labeled quantities, and a short narrative interpretation for each problem. Show every step; a correct final number without a visible derivation receives partial credit at most, and quoting a lecture number without adapting it to this problem's specific inputs receives no credit for that step.
OpenStax Astronomy 2e (local extracted reference copy: references/openstax-astronomy-2e-extracted.txt) covers the Sun in Chapter 15 ("The Sun: A Garden-Variety Star"): 15.1 The Structure and Composition of the Sun, 15.2 The Solar Cycle, and 15.3 Solar Activity above the Photosphere. Chapter 15’s section numbering was cross-checked directly against its own embedded figure numbering this session (Figures 15.1 through 15.24 all appear under their matching section headers with no offset), so this citation is verified against the local extracted text rather than extrapolated by analogy from a prior course. OpenStax’s treatment throughout Chapter 15 is descriptive and qualitative; nearly every quantitative derivation in this course (the hydrostatic solar-atmosphere/scale-height argument, the sunspot magnetic-pressure balance, the Parker solar-wind critical-point argument and its numerical transonic solution, flare free-energy budgets, the Chapman-Ferraro magnetopause standoff distance, and the Dessler-Parker-Sckopke ring-current/Dst relation) goes well beyond OpenStax Astronomy 2e’s introductory level; each lecture states explicitly where this course extends beyond the assigned reading.
materials/ASTR370/data/ where referenced above.