<s>
Gyrokinetic	B-Algorithm
ElectroMagnetic	I-Algorithm
(	O
GEM	O
)	O
is	O
a	O
gyrokinetic	O
plasma	O
turbulence	O
simulation	O
that	O
uses	O
the	O
particle-in-cell	B-Algorithm
method	O
.	O
</s>
<s>
It	O
is	O
used	O
to	O
study	O
waves	O
,	O
instabilities	O
and	O
nonlinear	O
behavior	O
of	O
tokamak	B-Application
fusion	O
plasmas	O
.	O
</s>
<s>
GEM	O
uses	O
the	O
delta-f	O
particle-in-cell	B-Algorithm
(	O
PIC	O
)	O
plasma	O
simulation	O
method	O
.	O
</s>
<s>
GEM	O
uses	O
a	O
two-dimensional	O
domain	B-Algorithm
decomposition	I-Algorithm
(	O
see	O
domain	B-Algorithm
decomposition	I-Algorithm
method	I-Algorithm
)	O
of	O
the	O
grid	O
and	O
particles	O
to	O
obtain	O
good	O
performance	O
on	O
massively	O
parallel	O
computers	O
.	O
</s>
<s>
A	O
Monte	B-Algorithm
Carlo	I-Algorithm
method	I-Algorithm
is	O
used	O
to	O
model	O
small	O
angle	O
Coulomb	O
collisions	O
.	O
</s>
<s>
GEM	O
is	O
used	O
to	O
study	O
nonlinear	O
physics	O
associated	O
with	O
tokamak	B-Application
plasma	O
turbulence	O
and	O
transport	O
.	O
</s>
<s>
Tokamak	B-Application
turbulence	O
driven	O
by	O
ion-temperature-gradient	O
modes	O
,	O
electron-temperature	O
gradient	O
modes	O
,	O
trapped	O
electron	O
modes	O
and	O
micro-tearing	O
modes	O
has	O
been	O
investigated	O
using	O
GEM	O
.	O
</s>
