A key mid-term goal for ALMA in the next decade is to increase its
effective collecting area.
The priority of this goal stems primarily from the need to study
diagnostic spectral lines
toward nascent solar systems, which currently can only be barely
detected in the nearest
examples, as well as toward the most distant known objects in the
high-redshift Universe.
In both cases, we must be able to image the line emission with high
resolution and fidelity and
to do so for meaningful sample sizes. An additional science motivation
for increased collecting
area is to improve ALMA's mapping speed to enable larger area surveys
despite the current
small field of view. I will briefly discuss options and challenges for
expanding ALMA's effective
collecting area with additional antennas, as well as focal plane arrays.
I will also describe how
these developments could impact the requirements for the Next ALMA
Correlator.
