# Open coronal hole

### No throat · adiabat 0.323 MK · Alfvén speed 6897 km/s · banked channel

**Date:** 2026-10-08
**Status:** **RECORD** · public page `/cosmology/coronal-hole`
**Parents:** measey.com `documents/a_geom_ft_stellar_condensation_cascade_chunk4.md` · `a_geom_coronal_two_accounts.md` · `PASS_FT_CH_CURRENT_FIRST`

> **\(A\propto r^{s}\) for \(B\propto r^{-s}\), and that area has no throat. A factor-of-ten density drop at \(\gamma=5/3\) takes \(1.5\,\mathrm{MK}\) to \(0.323\,\mathrm{MK}\). Along a field line the magnetic-pressure gradient is cancelled by tension. At \(10\,\mathrm{G}\) and \(n_p=10^{7}\,\mathrm{cm^{-3}}\), \(v_A=6897\,\mathrm{km\,s^{-1}}\). An isothermal Parker wind at \(0.8\,\mathrm{MK}\) is \(419\,\mathrm{km\,s^{-1}}\) at \(1\,\mathrm{AU}\).**

The \(0.8\)–\(1.0\,\mathrm{MK}\) band is a density ratio \(0.39\)–\(0.54\). Four percent alpha mass gives \(6763\,\mathrm{km\,s^{-1}}\). Parker speeds: \(1.0\,\mathrm{MK}\) gives \(485\,\mathrm{km\,s^{-1}}\), \(1.5\,\mathrm{MK}\) gives \(628\), \(2.0\,\mathrm{MK}\) gives \(752\). The fast-stream Alfvén speed at Earth for \(5\,\mathrm{nT}\) and \(3\,\mathrm{cm^{-3}}\) with the banked helium factor is \(58\,\mathrm{km\,s^{-1}}\).

The isothermal integral at \(0.8\,\mathrm{MK}\) reaches \(419\,\mathrm{km\,s^{-1}}\) at \(1\,\mathrm{AU}\) from a base speed of \(14.3\,\mathrm{m\,s^{-1}}\). The \(s=3\) solution reaches \(526\,\mathrm{km\,s^{-1}}\). A bulk \(1\,\mathrm{km\,s^{-1}}\) at \(R_\odot\) turns at \(1.55\,R_\odot\). See `a_geom_hole_momentum_integral.md`. The public sentence for the hole is footpoint shake, ion-circle handoff, and the outward mirror. The \(10\,\mathrm{G}\) mean and the \(1\,\mathrm{km\,s^{-1}}\) driver stay. The closed-loop \(1.73\,\mathrm{MK}\) package is a different region. Gate 5 stays unpaid. No ledger row. No promote. The wind bank stays `PASS_FT_CH_CURRENT_FIRST`.