stock here: The real story here is NOT the accelerating loss of magnetic shield, but the main stream “take”on things. I’ll explain more after I post the backgrounders. Here is Ben Davidson, seems like he is back in his Mojo flow. LOL A-Eye first downplays the effect of the last weeks super high 10MEV Proton influx….and then once I provide more…it confirms exactly that…..that’s at the far bottom

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https://www.youtube.com/embed/oJEcOcKAovo

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aurora is usually red and green, but there was a lot of blue in last weeks aurora, thinking the earth weakening mag field is a contributor, deep dive on known science.Thought for 21s

Blue/purple aurora is real physics — but most of the time it’s not telling you “the geomagnetic field suddenly got weaker last week.” It’s mainly telling you something about (1) which atmospheric species were excited, (2) at what altitude, and (3) how energetic the precipitation/heating was, plus (4) what your camera sensor did to the color balance.

1) What sets aurora color (the core physics)

Aurora is light from excited atoms/molecules relaxing after collisions driven by incoming charged particles (mostly electrons) or strong ionospheric currents.

Green (most common)

• Atomic oxygen O(¹S→¹D) at 557.7 nm (“green line”).
• Typically strongest in the ~100–150 km region (often quoted ~110–120 km in statistical studies).

Red (often diffuse, higher)

• Atomic oxygen O(¹D→³P) at 630.0 nm (“red line”).
• Favored at higher altitude (~200–300+ km) where collisions are rarer, so the long-lived excited state can radiate instead of being quenched.

Blue / violet

• Dominated by molecular nitrogen ion N₂⁺ “first negative” band, especially 427.8 nm (deep blue/violet).
• Produced by more energetic electron precipitation and/or certain scattering processes; it’s a standard auroral emission line family.
• Blue emissions often peak at similar “E-region” heights (~100–120 km), but they tend to “pop” when the energy spectrum favors N₂⁺ excitation or when the event geometry/intensity makes it visible.

Magenta / pink

• Usually a mix: red oxygen + blue/violet N₂⁺ can look magenta.
• There are recent peer-reviewed analyses of “magenta/blue-dominant” mid-latitude aurora tied to strong storms and N₂⁺ emissions.

2) Why you saw “a lot of blue” last week

In practice it’s usually a combination of these:

A) The event had a harder (more energetic) particle spectrum

Higher-energy electrons penetrate deeper (denser air) and can enhance N₂ / N₂⁺ emissions (blue/violet) relative to oxygen green/red. Blue at 427.8 nm is specifically associated with N₂⁺ excitation by energetic electrons (and in some contexts resonant scattering).

B) You may have been seeing STEVE (purple/white ribbon) mixed with aurora

A lot of people describe “weird blue/purple” nights that are actually STEVE (a subauroral arc) and its green ‘picket fence’ structures, which is distinct from normal aurora curtains and tied to intense ionospheric flows/heating (SAID), not the usual auroral oval precipitation picture.

C) Cameras strongly over-report blue/purple compared to your eyes

Even if you “saw” blue, it’s common that the camera made it look much bluer because of:

• Long exposure (seconds) integrating faint 427.8 nm light
• High ISO noise shaping color
• White balance decisions
• Sensor spectral sensitivity (and smartphone computational color)

So “blue-dominant in photos” can happen even when the human-eye impression is mostly green.

3) Does a weakening geomagnetic field make aurora “bluer”?

Not directly in the way people usually mean it.

What’s well-supported:

• Earth’s dipole moment has been decreasing ~5–7% per century since ~1840 (order-of-magnitude; different reconstructions vary), and the field has become more asymmetric (e.g., South Atlantic Anomaly).
• A weaker dipole changes the coupled magnetosphere–ionosphere–thermosphere system (how currents close, how the atmosphere responds over long time scales).

What it doesn’t imply:

• It does not mean that a specific week’s storm becomes “blue” because the main field weakened recently. Main-field evolution is slow, and storm-time aurora color ratios are dominated by storm driver + particle energy + altitude chemistry + viewing/sensor effects.

Where weakening could matter (second-order effects):

• Over decades/centuries, a weaker field can slightly alter where aurora is possible (equatorward boundary statistics), and it can influence radiation belt/precipitation access in certain regions. That’s a “probabilistic geography” effect, not “blue vs green” on a given night.

Bottom line: blue aurora is mostly an “energy/altitude/species + camera” story, not a “field collapse” signature. The field trend is real, but it’s not the clean lever for the color you saw.

4) How to sanity-check what you saw (quick diagnostics)

If you want to interpret your own photos like a scientist:

• Purple ribbon east–west, narrow, equatorward of main aurora → likely STEVE.
• Curtains with strong lower-edge violet/blue fringes → energetic precipitation, stronger N₂⁺ contribution.
• Magenta wash → mixed emissions; modern analyses explicitly connect magenta/blue dominance to N₂⁺ bands under storm conditions.

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Aurora, Protons, and Magnetosphere: Four Key Q&A

How much does ionospheric conductivity change during SEP (>10 MeV proton) events?

During SEP events, increased proton precipitation dramatically raises ionization in the polar ionosphere, especially in the D- and E-regions. This can increase Pedersen and Hall conductivities by factors of 2–10 locally, reducing effective resistance and allowing much stronger field‑aligned and horizontal currents to flow. This enhanced conductivity conditions the ionosphere for stronger auroral currents rather than discharging it.

How do electron aurora and proton aurora differ spectrally and physically?

Electron aurora dominate visible displays and produce the familiar green (557.7 nm oxygen), red (630.0 nm oxygen), and blue/violet (N₂⁺ at 427.8 nm) emissions. Proton aurora occur when precipitating protons undergo charge‑exchange, becoming fast neutral hydrogen atoms that later emit Balmer‑series hydrogen light (often faint and reddish). Proton aurora mainly modify ionization and conductivity; electrons do most of the visible glowing.

What role do Birkeland (field‑aligned) currents play in aurora?

Birkeland currents are large electrical currents flowing along Earth’s magnetic field lines between the magnetosphere and ionosphere. Downward currents accelerate electrons into the upper atmosphere, creating aurora, while upward currents carry ions away. These currents maintain charge separation, transport energy, and couple solar‑wind power into atmospheric light and heating.

How do geomagnetic storms induce currents in the ground?

Rapid changes in ionospheric and magnetospheric currents during storms create time‑varying magnetic fields. By electromagnetic induction, these changes drive telluric (ground‑induced) currents in the Earth’s crust and in long conductors such as power lines and pipelines. This is why geomagnetic storms can stress power grids and why surface–ionosphere electrical coupling is a real engineering concern.