Roles of ion state and plasma on evolution of planet and biosphere

Roles of ion state and plasma on evolution of planet and

biosphereM. Yamauchi and J.-E. Wahlund

Swedish Institute of Space Physics (IRF) Kiruna, Sweden

M.Yamauchi@irf.se

Fact 1: unexpected high loss rate ~ 1 kg/s

vH+

nH+

nO+

nO2+

Even higher flux is observed for the Earth (100~500 ton/day).Lundin et al., 1990

Fact 2: Magnetic field-dependent ion reaction

During the evolution of biosphere in the ancient Earth, Venus, and Mars, ionized state (weakly ionized plasma) could have played important roles on: (1) Determination of initial atmosphere and its evolution by the direct interaction between the ionosphere and solar wind.

(2) Chirality formation by the asymmetric chemical reactions of ionized molecules in the ionosphere or under shallow water.

(3) Atmospheric evolution by the non-thermal dynamics of ions

Planetary formation

( (1))

Formation of atmosphere (and water)

( (2) ?)

Formation (or arrival) of amino acid

( (2) ?)

Formation of RNA

( (3))

Evolution of atmosphere (and biosphere)

Importance of plasma: three possible episodes

Note : chirality formation

(a) Choose the combination of L-type amino & D-type sugar

(b) Choose "right-handed helicity" of RNA

This is previously presented (1998, 2001)

Today's keyword : Ionosphere / ion circulation

1. Controls the solar wind interaction for the non-magnetized planet.

2. Chiral environment of the ionosphere (presented 2001).

3. Source and sink of escaping ions.

The evolution of the planetary atmosphere might be dependent on the ionospheric condition and its activity.

Add another aspect on the solar UV dependence and solar wind (PD = v2 and IMF*) dependence.

*IMF = Interplanetary Magnetic Field (=B)

1. Solar wind (SW) interaction with ionosphere

shocked SW

Magnetized planet

SW is stopped by the magnetic pressure of the dipole field

Un-magnetized planet

Magnetized SW

Interplanetary magnetic field (IMF) piles up around the ionosphere due to induction current

Un-magnetized planet

Un-magnetized SW

present Earth, ancient Earth?

Mars, Venus, ancient Earth? For reference

Weakly or un-magnetized planet (Mars, Venus, ancient Earth?)

Four loss mechainsms:

(1) Collisional interaction by the solar wind: small for our Sun

(2) Thomson scattering by solar UV raduation: small for our Sun

(3) Thermal escape: small for the Earth, Mars, and Venus

(4) EM interaction (non-thermal): large

Ion Pickup process: believed to be the largest contribution for non-magnetized planet. Newly ionized atoms inside the solar wind EM field (i.e., beyond the boundary) start making a cycloid trajectory and escape.

Ion pickup loss vs. planetary corona

(1) If Extent of ionosphere > Extent of neutral atmosphere (strong UV?)

Narrow magnetic piled up region above the ionosphere

Balance between SW PD ( piled up magnetic field) Pionosphere

(a) stronger (stable) IMF same amount of the magnetic pile up

(b) more variable IMF more internal process (non-thermal escape)

(c) stronger SW PD lower balance altitude more neutral beyond boundary more ion pickup

(2) If Extent of ionosphere < Extent of neutral atmosphere (weak UV ?)

Thick (spread) magnetic pile-up region above the ionosphere

Balance between SW PD Pexosphere

Neutrals are quickly blown off (by ion pickup) all existing models

Magnetized planet (Earth, Mercury)

Magnetopause : balance between SW PD Planetary magnetic field

(a) stronger but stable IMF lower altitude of magnetopause but more return flow

(b) more variable IMF more internal process (non-thermal escape)

(c) stronger SW PD lower altitude of magnetopause + escape

How about UV dependence ? (important for ancient condition)

Height and density of the ionosphere

(1) Ionization (source) = Chapman model One-component atmosphere (scale height = H 1/gravity): cross section, F0:incoming solar flux, n0:density at z=0

Peak altitude : zmax(, F0, H) = H ln(n0H/cos()) does not depends on F0 , but on H (i.e., gravity)

Peak production : qmax (, F0 , H) = F0cos()/H exp(1) depends on F0 and H (i.e., gravity)

(2) Transport (recombination loss is ignorable) Moves peak of ne(z) much higher with less sharp ne(z) profile

Transport (convection) is mainly driven by heating ( q) Ionospheric extent depends on both F0 and gravity

Ionosphere (cont.)After http://ion.le.ac.uk/ionosphere/profile.html

Ionization (model): peak at < 150 km

Ion density (observation): peak at 300~400 km

(1) Transport is important

(2) Solar flux is important

UV depedenceStronger UV higher, hotter, denser ionosphere

(1) For magnetized planet

but same magnetopause location

more neutral beyond the magnetopause & more upflowing ions (particlarly inside cusp)

more escape

(2) For un-magnetized planet

higher magnetic pileup location but higher neutral corona extent

As total, most likely less neutral beyond the boundary

less escape? In fact, more escape of cold ions from Titan than from Venus

Ancient Earth's ionosphere: many possibilities* Magnetized or non-magnetized* High UV period or low UV period* Strong/active or weak/quiet IMF* Strong or weak SW pressure* Upper atmospheric neutral temperature (i.e., composition)

Most likely more escape (for selective ions) forstronger SW dynamic pressuremore variable IMFhigher neutral temperature

and forstronger UV (magnetized planet)weaker UV (un-magnetized planet)

What can we learn from present ?

Mars : quick energization of O+ is confirmed

Lundin et al., 2004

Magnetized Earth: O+ is escaping

Non-thermal O+ (> 10 eV = 10 km/s = escape velocity) are frequently found above the Earth's ionosphere. (Nilsson et al., 2004)

H+

O+

Dynamics of ionospheric origin ions (obs.) !

(1) Pickup process: Induction current of the ionosphere piles up the IMF for both Mars and Venus. Ion pickup loss takes place beyond this boundary.

(2) Non-pickup process: Non-thermal ion escape is substantial for both Earth and Mars. Non-thermal ion circulation cannot be ignored in the planetary evolution time scale (although the pickup loss is probably the largest contribution for non-magnetized planet).

Note : non-thermal escape/return/circulation route/mechanism is far more complicated than simple thought.

Distribution of ion heating at h = 1700km

(Broad-Band Electrostatic Low Frequency wave)

(Lower Hybrid or Electro-Magnetic Ion Cyclotron wave)

(1) Escapes are in various forms

(2) dependent strongly on SW/magnetospheric condition

Freja statisticsNorqvist et al., 1998

Earth : Many different non-thermal O+ escapes

Arverius et al., 2006

(1) Additional mechanism at high altitude

(2) Dependent on SW condition in various ways

O+ injection : it returns (we don't know the amount)

Yamauchi et al., 2005

Budget above the Earth's ionosphere

ion escape H+ O+

< 10 eV (2~3 Re) 2~5 1~3

> 10 eV (3~4 Re) 2~8 1.5~20

ion precipitation ion electron

> 10 eV (DMSP) 0.2~0.9 9~60in 1025 /s

mass budget H+ O+ meteors

out 0.05~0.2 0.5~5 -

in < 0.02 ? 0.5

in kg/sAfter Moore et al., 1999

H+/O+ in major return route

correlated & anti-correlated

Summary on the ion circulation1. There are more mechanism of ion escape/return from/to the ionosphere than a simple thought. Even now, we have many un-understood ion escape/return mechanisms.

2. Role of the ionosphere is not limited to the source/sink of circulation, but to determine the boundary beyond which the atmosphere is lost.

3. For both cases, the ionospheric effect on the atmospheric escape is a complicated function of solar flux, SW, and IMF for both magnetized and un-magnetized planet.

Thus, the ionized state (weakly ionized plasma) could have played important roles during the evolution of biosphere in the ancient Earth, Venus, and Mars. We need both static and dynamic conditions of ancient Earth for proper modeling of atmospheric condition.

Chirality : mirror asymmetry

Neutral : linear Ionized : chiral

Possible causes of chirality1. By chance + competition/auto-catalysis?

2. Chiral forces + competition/auto-catalysis? 2b. Weak Boson interaction force

W-interaction force / Z-interaction force (a) 2b. Polarized Electromagnetic (EM) radiation

gamma ray (a) / UV-IR light (b) / radio wave (c, d)

3. Achiral forces + competition/auto-catalysis? 3a. Radiation or Discharge in anisotropic environment

in magnetic field (a-d) in electric/gravity field (a-d) in plasma (a-d, f)

3b. Chiral reaction environment with Lorentz force + electrostatic force (c, e-i) + magnetostatic force (e, h-i) + non-EM forces, e.g., g, P, centrifugal, etc. (f-i)

(a) cosmic ray (b) solar radiation (c) lightning (d) from ionosphere (e) catalytic/polarized layer or boundary

(f) partially ionized fluid (g) laminar convection (h) shock propagation

(i) strong gradient of ionized solution

3b. Chiral reaction environment

Particle-1: at least 2 axes of attitude fixed.

Particle-2 or boundary: approach from one side (along 3rd axis direction of particle-1).

3rd axis

COOH

C

NH2

Weakly ionized plasma = Chiral environment!

To make the ion motion direction stay relatively fixed while electron obey Lorenz force, we need frequent collisions with neutral. A weakly ionized state (ionosphere!) is favourable.

miui = [iFi + Fi Ωi] / [i2 + Ωi

2]

where Fi = qiE + mig Ωi = qiB/mi

If i >> Ωi

ui = Fi/mii+ Fi Ωi/mii2

Almost all particles move in the F = qE + mg direction, whereas the attitude is controlled by E and B directions if the molecule has both the electric and magnetic dipole moments.

Summary on the Chirality

Role of the ionosphere and ionized state is not limited to above, but it could have played a role in making chiral reaction.

Low temperature = higher chance of chiralityThe degree of fixing of a "free" n-particle system by the static magnetic field against the ordinary thermal motion:

∆ ≈ (µB·E/kT)·nµB·E + (µE·E/kT) · nµE·E

∆: total energy shift due to the external magnetic field

µB: magnetic moment of the molecule

µE: electric dipole moment of the molecule

e.g., electron in the geomagnetic field (B=10-4 T) at room temperature (kT = 0.02 eV).

µB·B/kT ≈ 10-6 /molecule « 1

∆ ≈ 10-14 eV/molecule : comparable to weak interaction force

In reality, we havd other fixing factors e.g., boundaries and laminar catalyst.

Low-temperature chemistry : example

Not only ionosphere, but also….

Mars : finding the signature of ancient Martian life should be highest inside the region of the magnetic stripe.

Interstellar cloud : B (magnetic field) is weak and density is low although T (temperature) is very low. Hence the assistance of polarized radiation has been favoured. Otherwise, we only need the i >> Ωi condition for

the chiral environment. Note that the low density favours the partial ionization. The external force (e.g., gravity) can be temporally enhanced when the cloud floats by a star.

Comet in magnetized solar wind : A similar argument is possible because it is not difficult to find a region of i >> Ωi near the comet surface.

Accidental planetary flybys provide extra gravitational force.

Finally, near the underwater volcano :

Ancient planet (Earth, Venus, Mars)a wild guess for the magnetized case

Chiral underwater reaction near volcano

Force-free (lowest energy) configuration

Duct structure by whistler wave

Critical ionization velocity (CIV) phenomenon

Chiral reaction in weakly-ionized plasma

Escape from the cusp

Earth ?

Mars ?

Venus ?

Io & other

Satellites?

O+ source ≠ H+ source

H+

O+

H+

O+

H+

O+

O+ injection (Freja statistics)

Distribution of heavy ion injection events at 0.1-10 keV range. One can recognize nightside preference.

More than two types of O+ escape

~ 1 kg/s loss means complete loss in 200 M year without refill