If you took a video of the KI in the low energy state "bleached" with room lights on and then turned on the tesla coil leaving the room lights on maybe you could see the color change. Then turning off the tesla coil the color decay could maybe be seen. I've seen this done with mineral demos of tenebrescence but they usually turn off the room lights during the short wave UV activation to show the fluorescence.

Here is the Python code. you need the Phyphox app on the phone.  I have an android not sure about iphone. I wrote my own quaternion module let me know if you need that.

import sys
import pygame
from pygame.locals import *
from OpenGL.GL import *
from OpenGL.GLU import *
from math import *
import numpy as np
import requests
import quaternions as qu

x,y,z = 1.25,2.5,.25
vertices = (
    (x, -y, -z),
    (x, y, -z),
    (-x, y, -z),
    (-x, -y, -z),
    (x, -y, z),
    (x, y, z),
    (-x,-y, z),
    (-x, y, z)
    )

faces = (
    (0,1,2,3),
    (3,2,7,6),
    (6,7,5,4),
    (4,5,1,0),
    (1,5,7,2),
    (4,0,3,6)
    )

colors = (
    (0.,1.,0.),
    (1.,0.,0.),
    (0.,0.,1.),
    (1.,1.,0.),
    (1.,0.,1.),
    (0.,1.,1.)
    )

def quads():
    cindx = 0
    glBegin(GL_QUADS)
    for face in faces:
        glColor3fv(colors[cindx])
        for vertex in face:
            glVertex3fv(vertices[vertex])
        cindx += 1
    glEnd()       
           
# phyphox comm settings
PP_ADDRESS = "http://192.168.1.3:8080"
PP_CHANNELS = ["accX", "accY", "accZ","gyr_time","gyrX", "gyrY", "gyrZ",
            "magX", "magY", "magZ"]
#PP_CHANNELS = ["acc_time","accX", "accY", "accZ"]# accelerometer data names
#PP_CHANNELS = ["gyr_time","gyrX", "gyrY", "gyrZ"] # gyro data names
#PP_CHANNELS = ["magX", "magY", "magZ"] # magnetometer data names
start = PP_ADDRESS +"/control?cmd=start"
stop = PP_ADDRESS +"/control?cmd=stop"
clear = PP_ADDRESS +"/control?cmd=clear"
url = PP_ADDRESS + "/get?" + ("&".join(PP_CHANNELS))
ax,ay = 0.,0.


def main():
    m, e, u, qf = np.zeros((3,3)),np.zeros(3),np.zeros(3),np.zeros(4)
    b, n, q, dqg = np.zeros(3),np.zeros(3),np.zeros(4),np.zeros(4)
    wu = np.zeros(3)
    wtl = 0.
    crd, twopi = 180./pi, 2*pi
    fac = .9  #  filter parameter
    pygame.init()
    display = (1333,1000)
#    aspr = float(display[0])/display[1]
    aspr = 1.5
    pygame.display.set_mode(display, DOUBLEBUF|OPENGL)
    glEnable(GL_CULL_FACE)
    glFrontFace(GL_CW) # face vertex winding order is CW
#    gluPerspective(45, (display[0]/display[1]), .1, 50.)
    s = 7.
    glOrtho(-s*aspr,s*aspr,-s,s,0.1,50.)
    glTranslatef(0,0,-5)
    glRotated(-90.,1,0,0)
    glRotated(-90.,0,0,1)

   
    data = requests.get(start).json() # start comm with phyphox
   
    while True:
        for event in pygame.event.get():
            if event.type == pygame.QUIT:
                pygame.quit()
                data = requests.get(stop).json() # stop comm with phyphox
                quit()

        data = requests.get(url=url).json()
        ax = data["buffer"][PP_CHANNELS[0]]["buffer"][0]
        ay = data["buffer"][PP_CHANNELS[1]]["buffer"][0]
        az = data["buffer"][PP_CHANNELS[2]]["buffer"][0]
        wt = data["buffer"][PP_CHANNELS[3]]["buffer"][0]
        wx = data["buffer"][PP_CHANNELS[4]]["buffer"][0]
        wy = data["buffer"][PP_CHANNELS[5]]["buffer"][0]
        wz = data["buffer"][PP_CHANNELS[6]]["buffer"][0]
        bx = data["buffer"][PP_CHANNELS[7]]["buffer"][0]
        by = data["buffer"][PP_CHANNELS[8]]["buffer"][0]
        bz = data["buffer"][PP_CHANNELS[9]]["buffer"][0]

        if str(ax) != 'None' and str(wt) != 'None' and str(bx) != 'None' :

# use acceleromter and magnetometer data to construct rotation matrix
            u[:] = ax, ay, az
            umag = sqrt(u.dot(u))
            u /= umag
            b[:] = bx, by, bz
            e = np.cross(b,u)
            emag = sqrt(e.dot(e))
            e /= emag
            n = np.cross(u,e)
            m[0] = e
            m[1] = n
            m[2] = u
# convert rotation matrix to quaternion qam
            qam = qu.mat2q(m)
            if wtl == 0.:
              qf, wtl = qam, wt
# compute delta rotation quaternion from gyro data
            dwt = wt - wtl
            if dwt > .2:
              dwt = .2
            print(wx, wy, wz, wt, wtl, dwt)
            wtl = wt
            wu[:] = wx, wy, wz
            wmag = sqrt(wu.dot(wu))
            wu /= wmag
            thao2 = wmag*dwt/2.
            sthao2 = sin(thao2)
            dqg[:] = cos(thao2), wu[0]*sthao2, wu[1]*sthao2, wu[2]*sthao2
            qg = qu.q_mult(dqg,qf)
            qf = qu.Slerp(qam,qg,fac)

        glClear(GL_COLOR_BUFFER_BIT|GL_DEPTH_BUFFER_BIT)
# draw object with it's own screen positon           
        glPushMatrix()
        glTranslatef(0,-4.25,0)
        tha = 2*acos(qam[0])
        glRotated(tha*crd,qam[1],qam[2],qam[3])
        quads()
        glPopMatrix()


# draw object with it's own screen positon           
        glPushMatrix()
        glTranslatef(0,4.25,0)
        tha = 2*acos(qf[0])
        glRotated(tha*crd,qf[1],qf[2],qf[3])
        quads()
        glPopMatrix()

        pygame.display.flip()
        pygame.time.wait(1)   
main()


I made a expansion cloud chamber ten years ago. An advantage of the expansion cloud chamber is no dry ice is required and the sensitive volume can have a large vertical dimension which is good for cosmic ray studies. The advantage of a dry ice diffusion cloud chamber is that it's continuously sensitive and fairly simple to construct. Here is a video compilation of a few expansions of the chamber. The head of the pin inside the chamber is coated with radium paint and shows alpha particle tracks.   

Having a top dome that surrounds the upper pully and collector is the key to a VDG achieving very high voltages because of the Friday Ice Pail effect. Once charge is placed inside the dome it can  transfer completely to the dome no matter what voltage the dome is. Without the dome, if one lead of a capacitor is connected to the upper collector and the other lead is connected to ground. The capacitor would only charge up to the voltage of the charge to ground.

Wikipedia has a good description under "projection method (fluid dynamics)". The accuracy of Jos Stam's method is a good question and I don't know. A test case used a lot is the flow past a cylinder. The vortex shedding frequency vs Reynolds number for a cylinder is very well studied. I've setup this case for two other fluid simulations and should do it for this one.

Suminagashi simulation.

2D fluid simulation from “Real-Time Fluid Dynamics for Games” by Jos Stam coded in C. Tracer particle dynamics was added.

Graphics done in Python and Matplotlib.

Video editing done in Blender.

Music:
“Hopeful Freedom” by Asher Fulero
YouTube Audio Library.

I'm glad were getting the same numbers! are you getting a closed form solution? I got a nasty first order nonlinear differential equation that I could only solve numerically. I agree that 10m is too large. The height to the top of the terminal is only 77 cm. Of course the actual geometry is far from spherically symmetric.

I modeled my VDG terminal in FEMM to see what the E field magnitude looked like around it's surface. The terminal voltage was set 100kV. The results are shown below. It's seen that the max E field magnitude is about 1.5*10^6 V/m and occurs at the lower outside of the terminal  Assuming air breaks down at 3*10^6 V/m this predicts a max terminal voltage of only 200kV. I'm guessing the space charge due to corona is why the terminal can go higher than this. I haven't figured out how to model this space charge. Does anyone have any ideas? Uspring?
 

  It's been hot and windy so I decided to do some field mill voltage measurements in the garage. The field mill reading was jumping around between about 3.6 and 4.3 volts and got to this level within a second of turning on the VDG. Not the steady increase that I remembered. It occurred to me that the measurement I was remembering was with a much smaller VDG and a slightly different field mill.
The field mill I'm using now is setup for fair weather atmospheric field measurements and is very sensitive and has a very long power and signal cable. The first thing I tried was shielding this cable. No luck the reading was still jumping around. Next I tried shielding the AC power and house ground cable going to the VDG with a separate Earth ground. No difference. There is a tenth of second time constant low pass filter on the field mill signal output and the current output of the VDG is very steady. This made No sense! I started to run out of ideas and began randomly trying stuff. This went on for a few days until I put a 25 cm stainless sphere on top of the VDG terminal. Suddenly the readings steadied and only moved around by about a tenth of a volt every few seconds. The only theory I have for this is that the extra capacitance of the sphere helps smooth out voltage variations on the terminal caused by random corona/streamer breakout.
  With the 25 cm sphere on top of the VDG terminal the field mill was placed so it read about -5 volts with the VDG running. From linearity tests I done the field mill is fairly linear in the range of -8 to +8 volts. The zero field reading is -0.1 volts (caused by a small misalignment in the synchronous rectifier) The actual reading with the VDG running was -4.9 volts and correcting for the zero field reading gives -4.8 volts (The VDG charges negative).
 To compensate for the ion cloud, objects in the garage charging and the VDG column charging I quickly grounded the terminal after turning off the VDG and noted the field mill reading.
I was expecting a value a little more negative that -0.1 zero field value, but the value was close to zero! A value of zero means a net positive field and that makes no sense so no attempt was made to make this compensation.
  Field mill calibration was done by first making sure the VDG and field mill did not move and anything else in the garage did not change. I tried to keep my body as far away for the VGD and field mill as possible during both the calibration and VDG running readings. One terminal from a 15kV by 30ma NST was half wave rectified to a 225 pF HV capacitor. The voltage on this capacitor was controlled by a variac feeding the NST. The variac was adjusted until the current thru a 1 Gohm HV resistor read 10 uA indicating a voltage of 10 kV. This voltage was then applied to the VDG terminal via a 71 Mohm HV resistor in series with an electrode see photo below the resistor is inside the white tubing and can't be seen. It was found that the field mill was reading about -0.2 volts before even touching the electrode to the VDG terminal. To compensate for this the electrode was touched to the terminal then quickly taken off the terminal and placed on the ground and the variac was switched off. The field mill reading was then taken as quickly as possible. The field mill reading was dropping about 0.02 volts every few seconds so I have good confidence in this reading. After doing this calibration about five times all the values were close to -0.27 volts and correcting for the zero field value gives -.17 volts giving a calibration factor of 10kV/.17V = 58.8 kV/V. Applying this to the running VDG reading of -4.8 volts gives a voltage reading of  -282 kV. A little lower than all the other measurements.

Sphere gap: -310 kV
lifting disk:  -324 kV
field mill:     -282 kV

I'd guessed that you were putting the disks on top of the 10" sphere you were using for your spark tests.  Any reason not to do that?

I was worried about field distortion at the top of the sphere caused by the VDG terminal and prime conductor. I was less worried about this distortion for the sphere gap because the second sphere is directly behind the first sphere and assumed some shielding is provided by the first sphere. This is pure guess work on my part.