L03: reconstruct convection-cell, lid-regimes, tidal-flexing schematics

Add matplotlib reconstruction scripts for the three remaining L03
schematic figures:

- fig:convection-cells (Rayleigh-Bénard cell with hot/cold TBLs and
  alternating plumes)
- fig:lid-regimes (mobile-lid vs stagnant-lid two-panel schematic)
- fig:tidal-flexing (periapsis vs apoapsis tidal-bulge cartoon)

All three regenerate the existing AVIF in place and are pure
matplotlib (no external data). Captions in heat_energy.md now point
at the generating script. manifest.csv updated.

Closes the L03 figure-reconstruction batch.

Author: timlichtenberg

book/03_heat_energy/figures/lid_regimes.avif

@@ -165,7 +165,7 @@ Inside solid planetary interiors, radiation is generally less important than con
 :width: 600px
 :align: center
 
-Schematic of Rayleigh-Bénard convection. A fluid layer of depth $d$ is heated from below ($T_h$, hot bottom plate) and cooled from above ($T_c$, cold top plate). Hot fluid rises in plumes through a thin hot thermal boundary layer (TBL) at the base; cold fluid sinks through a thin cold TBL at the top. Lateral flow along the boundary layers closes the circulation. Convection sets in once the Rayleigh number exceeds the critical value $\mathrm{Ra}_c$ (Eq. {eq}`eq:rayleigh-number`). Custom schematic.
+Schematic of Rayleigh-Bénard convection. A fluid layer of depth $d$ is heated from below ($T_h$, hot bottom plate) and cooled from above ($T_c$, cold top plate). Hot fluid rises in plumes through a thin hot thermal boundary layer (TBL) at the base; cold fluid sinks through a thin cold TBL at the top. Lateral flow along the boundary layers closes the circulation. Convection sets in once the Rayleigh number exceeds the critical value $\mathrm{Ra}_c$ (Eq. {eq}`eq:rayleigh-number`). Custom schematic. Generated by `scripts/figures/L03_heat_energy/fig_convection_cells.py`.
 ```
 
 ### Comparison
@@ -380,7 +380,7 @@ Most other rocky bodies in the solar system (including Venus, Mars, Mercury, and
 :width: 750px
 :align: center
 
-End-member tectonic regimes for rocky planets. **Mobile lid (left):** the cold thermal boundary layer breaks into rigid plates that subduct at convergent margins, recycling lithosphere into the mantle and concentrating volcanism at ridges and hotspots; this is Earth. **Stagnant lid (right):** the boundary layer remains immobile and heat escapes by conduction through the lid, with episodic volcanic eruptions punching through; this is Mars, Venus, Mercury, and the Moon today. Custom schematic.
+End-member tectonic regimes for rocky planets. **Mobile lid (left):** the cold thermal boundary layer breaks into rigid plates that subduct at convergent margins, recycling lithosphere into the mantle and concentrating volcanism at ridges and hotspots; this is Earth. **Stagnant lid (right):** the boundary layer remains immobile and heat escapes by conduction through the lid, with episodic volcanic eruptions punching through; this is Mars, Venus, Mercury, and the Moon today. Custom schematic. Generated by `scripts/figures/L03_heat_energy/fig_lid_regimes.py`.
 ```
 
 Why Earth has plate tectonics while other rocky planets do not is one of the major unsolved problems in geophysics. Factors likely include:
@@ -478,7 +478,7 @@ On a circular orbit, a tidally locked moon maintains a constant distance from it
 :width: 700px
 :align: center
 
-Origin of tidal heating on an eccentric orbit. **Left:** at periapsis ($r=a(1-e)$) the moon is closest to the planet and the raised tidal bulge is largest. **Right:** at apoapsis ($r=a(1+e)$) the bulge is smallest. The cyclic flexing of the body's shape on each orbit dissipates orbital energy as heat at a rate $\dot E_\mathrm{tidal}\propto e^2/Q$, where $Q$ is the tidal quality factor (orbital geometry exaggerated for clarity). Custom schematic.
+Origin of tidal heating on an eccentric orbit. **Left:** at periapsis ($r=a(1-e)$) the moon is closest to the planet and the raised tidal bulge is largest. **Right:** at apoapsis ($r=a(1+e)$) the bulge is smallest. The cyclic flexing of the body's shape on each orbit dissipates orbital energy as heat at a rate $\dot E_\mathrm{tidal}\propto e^2/Q$, where $Q$ is the tidal quality factor (orbital geometry exaggerated for clarity). Custom schematic. Generated by `scripts/figures/L03_heat_energy/fig_tidal_flexing.py`.
 ```
 
 The tidal heating rate depends on:

book/03_heat_energy/figures/rayleigh_benard_schematic.avif

@@ -0,0 +1,135 @@
+"""Generate Fig. (`fig:convection-cells`).
+
+Schematic of Rayleigh-Bénard convection: a fluid layer of depth `d`
+heated from below at `T_h` and cooled from above at `T_c`, with thin
+hot and cold thermal boundary layers (TBLs) and alternating
+hot-rising / cold-sinking plumes that close the circulation.
+
+Caption / figure id : `fig:convection-cells`
+Markdown source     : book/03_heat_energy/heat_energy.md
+Citation key        : (textbook schematic)
+
+Pure schematic, no input data.
+"""
+from __future__ import annotations
+
+from pathlib import Path
+
+import matplotlib.pyplot as plt
+from matplotlib.patches import FancyArrowPatch, Rectangle
+
+from scripts.figures._shared.style import apply_style, save_figure
+
+
+REPO_ROOT = Path(__file__).resolve().parents[3]
+OUT_AVIF = REPO_ROOT / "book/03_heat_energy/figures/rayleigh_benard_schematic.avif"
+
+COLD = "#1f77b4"
+HOT = "#d62728"
+
+
+def make_plot() -> Path:
+    apply_style()
+    fig, ax = plt.subplots(figsize=(10, 5))
+
+    # Domain: x in [0, 10], y in [0, 5]; box from (0.5, 0.5) to (9.5, 4.5)
+    x0, x1 = 0.5, 9.5
+    y0, y1 = 0.5, 4.5
+    tbl_h = 0.4
+
+    # Outer hot/cold plates
+    ax.add_patch(Rectangle((x0, y1), x1 - x0, 0.25, color=COLD, alpha=0.85, zorder=1))
+    ax.add_patch(Rectangle((x0, y0 - 0.25), x1 - x0, 0.25, color=HOT, alpha=0.85, zorder=1))
+
+    # Convection cell box
+    ax.add_patch(Rectangle((x0, y0), x1 - x0, y1 - y0,
+                           fill=False, edgecolor="black", lw=1.4, zorder=2))
+
+    # Cold and hot TBLs (shaded inside box, top and bottom)
+    ax.add_patch(Rectangle((x0, y1 - tbl_h), x1 - x0, tbl_h,
+                           color=COLD, alpha=0.18, zorder=1.5))
+    ax.add_patch(Rectangle((x0, y0), x1 - x0, tbl_h,
+                           color=HOT, alpha=0.18, zorder=1.5))
+
+    # TBL labels
+    ax.text(x0 + 0.25, y1 - tbl_h / 2, "Cold TBL", color=COLD,
+            fontsize=10, va="center", ha="left")
+    ax.text(x0 + 0.25, y0 + tbl_h / 2, "Hot TBL", color=HOT,
+            fontsize=10, va="center", ha="left")
+
+    # Plate labels
+    ax.text((x0 + x1) / 2, y1 + 0.45, r"$T_c$ (cold)", color=COLD,
+            fontsize=13, ha="center", va="bottom")
+    ax.text((x0 + x1) / 2, y0 - 0.45, r"$T_h$ (hot)", color=HOT,
+            fontsize=13, ha="center", va="top")
+
+    # Plumes: alternating hot-rising / cold-sinking
+    plume_x = [2.0, 3.7, 5.5, 7.3, 9.0]
+    plume_kind = ["down", "up", "down", "up", "down"]
+    for px, kind in zip(plume_x, plume_kind):
+        if kind == "up":
+            ax.add_patch(FancyArrowPatch(
+                (px, y0 + tbl_h), (px, y1 - tbl_h),
+                arrowstyle="->", mutation_scale=18, color=HOT, lw=2.0))
+        else:
+            ax.add_patch(FancyArrowPatch(
+                (px, y1 - tbl_h), (px, y0 + tbl_h),
+                arrowstyle="->", mutation_scale=18, color=COLD, lw=2.0))
+
+    # Plume labels
+    ax.text(3.7, (y0 + y1) / 2, "Hot rising", color=HOT,
+            fontsize=11, ha="center", va="center",
+            bbox=dict(facecolor="white", edgecolor="none", pad=2))
+    ax.text(5.5, (y0 + y1) / 2, "Cold sinking", color=COLD,
+            fontsize=11, ha="center", va="center",
+            bbox=dict(facecolor="white", edgecolor="none", pad=2))
+    ax.text(7.3, (y0 + y1) / 2, "Hot rising", color=HOT,
+            fontsize=11, ha="center", va="center",
+            bbox=dict(facecolor="white", edgecolor="none", pad=2))
+
+    # Lateral boundary-layer flow arrows (start past the TBL labels)
+    ax.add_patch(FancyArrowPatch(
+        (x0 + 1.7, y1 - tbl_h / 2), (x0 + 3.2, y1 - tbl_h / 2),
+        arrowstyle="->", mutation_scale=12, color=COLD, lw=1.2))
+    ax.add_patch(FancyArrowPatch(
+        (x1 - 3.2, y1 - tbl_h / 2), (x1 - 0.7, y1 - tbl_h / 2),
+        arrowstyle="->", mutation_scale=12, color=COLD, lw=1.2))
+    ax.add_patch(FancyArrowPatch(
+        (x0 + 1.7, y0 + tbl_h / 2), (x0 + 3.2, y0 + tbl_h / 2),
+        arrowstyle="->", mutation_scale=12, color=HOT, lw=1.2))
+    ax.add_patch(FancyArrowPatch(
+        (x1 - 3.2, y0 + tbl_h / 2), (x1 - 0.7, y0 + tbl_h / 2),
+        arrowstyle="->", mutation_scale=12, color=HOT, lw=1.2))
+
+    # Heat in / heat out arrows outside box
+    ax.add_patch(FancyArrowPatch(
+        (x1 + 0.4, y1 + 0.1), (x1 + 0.4, y1 + 0.8),
+        arrowstyle="->", mutation_scale=15, color=COLD, lw=1.5))
+    ax.text(x1 + 0.6, y1 + 0.55, r"heat out $q$",
+            color=COLD, fontsize=10, va="center")
+    ax.add_patch(FancyArrowPatch(
+        (x0 + 0.6, y0 - 0.7), (x0 + 0.6, y0 - 0.1),
+        arrowstyle="->", mutation_scale=15, color=HOT, lw=1.5))
+    ax.text(x0 + 0.85, y0 - 0.45, r"heat in $q$",
+            color=HOT, fontsize=10, va="center")
+
+    # Depth indicator d on the right
+    ax.annotate("", xy=(x1 + 0.05, y0), xytext=(x1 + 0.05, y1),
+                arrowprops=dict(arrowstyle="<->", lw=1.0, color="black"))
+    ax.text(x1 + 0.15, (y0 + y1) / 2, r"$d$", fontsize=14, va="center")
+
+    ax.set_xlim(-0.2, 10.5)
+    ax.set_ylim(-0.6, 5.4)
+    ax.set_aspect("equal")
+    ax.axis("off")
+    fig.tight_layout()
+    return save_figure(fig, OUT_AVIF, avif_quality=80)
+
+
+def main() -> None:
+    out = make_plot()
+    print(f"  plot : {out}")
+
+
+if __name__ == "__main__":
+    main()

book/03_heat_energy/figures/tidal_flexing.avif

@@ -0,0 +1,146 @@
+"""Generate Fig. (`fig:lid-regimes`).
+
+End-member tectonic regimes for rocky planets: mobile lid (left,
+plate tectonics on Earth) vs stagnant lid (right, Mars / Venus /
+Mercury / Moon).
+
+Caption / figure id : `fig:lid-regimes`
+Markdown source     : book/03_heat_energy/heat_energy.md
+Citation key        : (textbook schematic; cited as Stevenson2003 / textbook)
+
+Pure schematic, no input data.
+"""
+from __future__ import annotations
+
+from pathlib import Path
+
+import matplotlib.pyplot as plt
+import numpy as np
+from matplotlib.patches import Ellipse, FancyArrowPatch, Rectangle
+
+from scripts.figures._shared.style import apply_style, save_figure
+
+
+REPO_ROOT = Path(__file__).resolve().parents[3]
+OUT_AVIF = REPO_ROOT / "book/03_heat_energy/figures/lid_regimes.avif"
+
+MANTLE = "#f5d3a0"   # warm sandy
+LID = "#5b8caf"      # blue-grey
+RED = "#d62728"
+BLUE_DK = "#1f4e79"
+GREY = "#444444"
+
+
+def draw_panel(ax, mode: str) -> None:
+    """Draw one panel; mode in {'mobile', 'stagnant'}."""
+    # Panel frame: x in [0, 10], mantle 0-3, lid 3-3.7, surface above 3.7
+    x0, x1 = 0.0, 10.0
+    y_floor = 0.0
+    y_lid_bottom = 3.0
+    y_lid_top = 3.7
+    y_top = 4.2
+
+    # Mantle
+    ax.add_patch(Rectangle((x0, y_floor), x1 - x0, y_lid_bottom - y_floor,
+                           color=MANTLE, zorder=1))
+    # Lid
+    ax.add_patch(Rectangle((x0, y_lid_bottom), x1 - x0, y_lid_top - y_lid_bottom,
+                           color=LID, alpha=0.85, zorder=1.5))
+
+    # Outline
+    ax.add_patch(Rectangle((x0, y_floor), x1 - x0, y_lid_top - y_floor,
+                           fill=False, edgecolor="black", lw=1.4, zorder=3))
+
+    ax.text((x0 + x1) / 2, 0.4, "core", color=GREY,
+            fontsize=10, ha="center", va="center", zorder=4)
+
+    if mode == "mobile":
+        ax.set_title("Mobile lid: plate tectonics (Earth)", fontsize=12, pad=8)
+
+        # Ridge in middle (small gap in lid)
+        ridge_x = 3.0
+        ax.add_patch(Rectangle((ridge_x - 0.07, y_lid_bottom),
+                               0.14, y_lid_top - y_lid_bottom,
+                               color="white", zorder=2))
+
+        # Two diverging arrows above ridge
+        ax.add_patch(FancyArrowPatch(
+            (ridge_x, y_lid_top - 0.05), (ridge_x - 1.0, y_lid_top + 0.4),
+            arrowstyle="->", mutation_scale=14, color=RED, lw=1.5, zorder=4))
+        ax.add_patch(FancyArrowPatch(
+            (ridge_x, y_lid_top - 0.05), (ridge_x + 1.0, y_lid_top + 0.4),
+            arrowstyle="->", mutation_scale=14, color=RED, lw=1.5, zorder=4))
+        ax.text(ridge_x - 1.2, y_top, "ridge", color=RED, fontsize=11, ha="left")
+
+        # Subducting slab: curved line plus tail
+        slab_t = np.linspace(0, 1, 50)
+        slab_x = ridge_x + 0.3 + 1.5 * slab_t
+        slab_y = y_lid_bottom - 1.6 * slab_t ** 1.6
+        ax.plot(slab_x, slab_y, color=BLUE_DK, lw=3.5, zorder=4)
+        # Arrow tip on slab
+        ax.add_patch(FancyArrowPatch(
+            (slab_x[-3], slab_y[-3]), (slab_x[-1], slab_y[-1]),
+            arrowstyle="->", mutation_scale=18, color=BLUE_DK, lw=3.0, zorder=4))
+        ax.text(slab_x[-1] - 0.1, slab_y[-1] - 0.3, "subducting\nslab",
+                color=BLUE_DK, fontsize=10, ha="center", va="top")
+
+        # Hotspot plume on right
+        hs_x = 7.5
+        ax.add_patch(FancyArrowPatch(
+            (hs_x, 0.6), (hs_x, y_top),
+            arrowstyle="->", mutation_scale=15, color=RED, lw=2.0, zorder=4))
+        ax.text(hs_x, y_top + 0.1, "hotspot", color=RED, fontsize=11, ha="center")
+
+    else:
+        ax.set_title("Stagnant lid (Mars, Venus, Moon)", fontsize=12, pad=8)
+        ax.text((x0 + x1) / 2, (y_lid_top + y_lid_bottom) / 2,
+                "rigid stagnant lid", color=BLUE_DK, fontsize=12,
+                ha="center", va="center", weight="bold", zorder=4)
+
+        # Conductive heat-loss arrows across lid (small upward grey)
+        for hx in [1.5, 4.5, 6.0, 8.5]:
+            ax.add_patch(FancyArrowPatch(
+                (hx, y_lid_top - 0.05), (hx, y_top),
+                arrowstyle="->", mutation_scale=10, color=GREY, lw=1.0, zorder=4))
+        ax.text(2.5, y_top + 0.05, "conductive heat loss",
+                color=GREY, fontsize=11, ha="center")
+
+        # Volcanism: thick red arrow puncturing the lid in middle
+        vx = 5.0
+        ax.add_patch(FancyArrowPatch(
+            (vx, 1.0), (vx, y_top),
+            arrowstyle="->", mutation_scale=18, color=RED, lw=2.6, zorder=5))
+        ax.text(vx, y_top + 0.05, "volcanism",
+                color=RED, fontsize=11, ha="center")
+
+        # Sub-lid convection cells (two ellipses with circulating arrows)
+        for cx in [2.5, 7.5]:
+            ax.add_patch(Ellipse((cx, 1.6), 2.4, 1.0, fill=False,
+                                 edgecolor=RED, lw=1.3, zorder=4))
+            # small arrow on ellipse to indicate direction
+            ax.add_patch(FancyArrowPatch(
+                (cx + 0.05, 1.1), (cx + 0.55, 1.4),
+                arrowstyle="->", mutation_scale=10, color=RED, lw=1.2, zorder=5))
+
+    ax.set_xlim(x0 - 0.3, x1 + 0.3)
+    ax.set_ylim(y_floor - 0.3, y_top + 0.6)
+    ax.set_aspect("equal")
+    ax.axis("off")
+
+
+def make_plot() -> Path:
+    apply_style()
+    fig, axes = plt.subplots(1, 2, figsize=(14, 4.6))
+    draw_panel(axes[0], "mobile")
+    draw_panel(axes[1], "stagnant")
+    fig.tight_layout()
+    return save_figure(fig, OUT_AVIF, avif_quality=80)
+
+
+def main() -> None:
+    out = make_plot()
+    print(f"  plot : {out}")
+
+
+if __name__ == "__main__":
+    main()