How do I solve an electron density continuity equation for Earth's atmosphere?

In summary, the conversation discusses solving a continuity equation for electron density as a function of time in Earth's atmosphere, with the assumption of neglecting vertical transport and the complete shut off of ion production rate at dusk. The conversation also mentions the effective recombination coefficient, and solving the equation with respect to density and time. A helpful resource for dealing with equations of this form is provided.
  • #1
Imagin_e
60
0

Homework Statement


Hi!

I need to solve a continuity equation for electron density as a function of time in the E-region of Earth's atmosphere. I shall neglect vertical transport and that the ion production rate completely shuts off dusk.

Homework Equations


See below

The Attempt at a Solution


Here is my attempt:

(1+λ)dNe/dt=p(t)-(1+λ)(αd-aλi)Ne2-Ne dλ/dt
Ne is the electron density, dy, λ=ratio of negative ions to electrons , p(t) is the electron production rate, αd is the recombination coeff. for ions and ai is the recombination coeff. negative ions with positive ions.

The effective recombination coefficient is: αeff=(1+λ)(αd+aλi).
If we assume that the is no negative ions, we get:
dNe/dt=p(t)-adNe2 (1)
and aeff simply becomes ad

Here comes the issue, I need to have a solution for equation (1) with respect to the density and time. . How should I integrate this? The density from the beginning is ≈ 1*109 m3 , which I calculated
 
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  • #2
There is a typo in equation ##(1)##. If I understand correctly you meant to write ##\alpha_d## not ##a_d##.

Equation ##(1)## has the form of a Riccati equation:

$$\frac{dN_e(t)}{dt} = p(t) - \alpha_d N_e^2(t)$$
$$y'(t) = p(t) + g(t)y(t) + f(t)y^2(t)$$

Where ##N_e(t) = y(t)##, ##p(t) = p(t)##, ##g(t) = 0##, and ##f(t) = \alpha_d##.

To learn how to deal with equations of this form, see: https://en.wikipedia.org/wiki/Riccati_equation#Reduction_to_a_second_order_linear_equation
 
  • #3
Zondrina said:
There is a typo in equation ##(1)##. If I understand correctly you meant to write ##\alpha_d## not ##a_d##.

Equation ##(1)## has the form of a Riccati equation:

$$\frac{dN_e(t)}{dt} = p(t) - \alpha_d N_e^2(t)$$
$$y'(t) = p(t) + g(t)y(t) + f(t)y^2(t)$$

Where ##N_e(t) = y(t)##, ##p(t) = p(t)##, ##g(t) = 0##, and ##f(t) = \alpha_d##.

To learn how to deal with equations of this form, see: https://en.wikipedia.org/wiki/Riccati_equation#Reduction_to_a_second_order_linear_equation
THANK YOU THANK YOU THANK YOU!
 

Question 1: What is electron density?

Electron density is a measure of the probability of finding an electron in a specific region of space. It is represented by a three-dimensional graph that shows the electron distribution around an atom.

Question 2: How is electron density calculated?

Electron density is calculated by squaring the wave function, which describes the behavior of an electron in an atom. This calculation takes into account the position, energy, and spin of the electron.

Question 3: What factors affect electron density?

Electron density can be affected by the number of electrons in an atom, the size of the atom, and the electronegativity of the atom. Other factors include the presence of nearby atoms and the presence of external electric or magnetic fields.

Question 4: Why is electron density important in chemistry?

Electron density is important in chemistry because it helps us understand the behavior of atoms and molecules. It can provide information about chemical bonding, molecular geometry, and reactivity. It is also used in interpreting spectroscopic data and predicting the properties of compounds.

Question 5: How is electron density related to electronegativity?

Electronegativity is a measure of an atom's ability to attract electrons towards itself. Higher electron density around an atom indicates a higher electronegativity, as the atom is more likely to attract electrons towards it. This can affect the polarity of bonds and the overall polarity of a molecule.

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