The ICON data file for jan 15 is a txt file, written out with the following IDL code chunk:
This file combines the green with the red line data at z=180 km for version v04.

filename=fileout
print,'writing out to file=',filename
openw,1,filename
printf,1,nzicon,nticon,dayicon,monthicon,yearicon
printf,1,zzkmicon
printf,1,timeUTicon
for it=0,nticon-1 do begin
  for k=0,nzicon-1 do begin
    printf,1, uvelicon(it,k),vvelicon(it,k), uvelerroricon(it,k),vvelerroricon(it,k),$
      lonicon(it,k),laticon(it,k), orbitnumicon(it,k), orbitadicon(it,k)
  endfor
endfor
close,1
print,'done writing to file',filename





These are the files i used to make the plots in the paper.  
the actual HIAMCM data is higher resolution (1/2 degree) and is finer in z.
You can request that data from Dr. Erich Becker if you'd like to have it.

The hiamcm data params file is ascii.
diff2000-0-400km_params_15JAN2022_00-23p9UT.hzti_zlev.txt  (Tonga run params)
nomeso-0-400km_params_15JAN2022_00-23p9UT.hzti_zlev.txt  (base run params)
you can read it in idl with this code fragment:
openr,1,fileparams
readf,1, nlon,nlat,nzre,ntre
print, 'nlon,nlat,nzre,ntre',nlon,nlat,nzre,ntre
nlon=fix(nlon+0.01) & nlat=fix(nlat+0.01) & nzre=fix(nzre+0.01) & ntre=fix(ntre+0.01)
lon=fltarr(nlon) & lat= fltarr(nlat) & zzkmre=fltarr(nzre) & timehrsre=fltarr(ntre)
lon=fltarr(nlon)
readf,1,lon
readf,1,lat
readf,1,zzkmre
readf,1,timehrsre
close,1
Here, nlon-# longitude pts, nlat=# lat pts, 
nzre=# z levels, ntre=# time pts in file.
lon=arry with longitudes
lat=arry with latitudes
zzkmre=arry with heights (in km)
timehrsre=arry with times on 15 jan 2022 (in hrs)


NEW: we now include the density in the HIAMCM files
the HIAMCM data files are binary files
diff2000-0-400km_15JAN2022_00-23p9UT.hzti_zlev_rho.dat  (Tonga run)
nomeso-0-400km_15JAN2022_00-23p9UT.hzti_zlev_rho.dat  (base run)
you can read them in idl with this code fragment:
    openr,1,filenametonga
    array=assoc(1,fltarr(nlon,nlat,nzre,ntre))
      uvel= array(0)  ; zonal velocity perturbation (m/s) 
      vvel= array(1)  ; meridional velocity perturbation (m/s)
      wvel= array(2)  ; vertical velocity perturbation (m/s)
      temp= array(3)  ; temperature (K)
      rho= array(4)  ; density (gm/m^3)
    close,1

; read from base file now.
    openr,1,filenamebase
      array=assoc(1,fltarr(nlon,nlat,nzre,ntre))
      uvelbase= array(0)  ; zonal velocity perturbation (m/s)
      vvelbase= array(1)  ; meridional velocity perturbation (m/s)
      wvelbase= array(2)  ; vertical velocity perturbation (m/s)
      tempbase= array(3)  ; temperature (K)
      rhobase= array(4)  ; density (gm/m^3)
    close,1