GEOPHYSICAL RESEARCH LETTERS, VOL. 28, NO. 13, PAGE 2669, JULY 1,2001
Correction
to "Particle-in-cell
simulations
of the lunar
wake with high phase space resolution"
Paul C. Birch and SandraC. Chapman
Spaceand Astrophysics
Group,PhysicsDepartment,Universityof Warwick,UK
In the paper entitled "Particle-in-cell simulationsof
speed(the scalingalterationhas changedthe scaleon
the lunar wakewith high phasespaceresolution"by
Paul C. Birchand SandraC. Chapman(Geophys.
Res.
Lett., 28, 219-222,2001)potentialstructures(shownin
figure3) with sharppeakededgestructureswereshown.
the X axis; the rarefaction wave is where the electron
densityis -• 0.8Nsw in the revisedfigure).The conclusionsof the paperare unaffected.The detailedresults
of thesenew simulationswill be published.
A scalingerror has sincebeen identified and the simulationshave been rerun. Figure 3 below is the correctedelectricpotentialsplot. Comparingthis to figure
3 in the paper, the main difference is the absenceof
20
the peakedstructureat Y = +IRL (hencethe absence
of enhancedelectrondensityat thosepoints). We still
find the samepotential drop at the beginningof the
simulation(althoughlargerin the revisedfigure,due
to the scaling),and the peakedstructuresdue to the
0
-e---20
-40
two-stream instability. Figure 2 below is the corrected
-60
2
electrondensityplot. Comparingthis to figure2 in the
40
paper, the main difference is the absence of enhanced
electron density at Y = +IRL. The rest of the structure is fundamentallythe same. The densityscalehas
Y(R
L)
-2 0
-X(RL)
changedsincethe electronsare now lessstronglyenFigure 3. A stackplotof electricpotentials(in unitsof
hancedin the centralwakeregion.We still seeescaping eV) calculated
fromelectricfielddata,plottedagainst
electronstructures,electrontwo-streaminstabilitycon- distancealongsimulationbox Y(R•) and time transfiningelectrons(andions)in the wake,anda rarefaction formedto a distancebehindthe moonX(R•), beginwave travelling away from the wake at the ion sound ning
at 5.5w• - 1.52R•,thenevery
2.8w• - 0.76R•.
0.8
ii 0.6
.:•
ß
-•:e•
.;•.
• .•.•..
•
-....•;-:-•'.•..
•c-,•.:,,.,•,.,..::...½...•z•:•:•.•z?::•:•..:•..•x.z•.;•&•7::c.•,•g
t...................
-2
0.2
-4
0
5
10
15
20
25
30
35
40
45
50
-X (RE)= Vconv
xt
Figure 2. Electron
density
evolution
shows
distance
alongsimulation
boxY(RL) against
time(distance
behind
moon)X(R•) with densitynormalised
to the ambientsolarwinddensity.
P. C. BirchandS.C. Chapman,SpaceandAstrophysics
Group,PhysicsDept., Universityof Warwick,Coventry,
CV4 7AL, UK. (e-mail:birch@astro.warwick.ac.uk)
Copyright2001 by theAmericanGeophysical
Union.
Papernumber2001GL012961.
(Received
February5, 2001; revisedFebruary22, 2001;
0094-8276/01/2001GL012961 $05.00
acceptedFebruary23, 2001.)
2669