Coauthors:
Category: Basic Research (Solar Physics)
Synopsis

1. Introduction

2. Scientific Motivation and Current Status
2.1 Forward Modeling
2.2 Numerical Simulations
2.3 Acoustic Halos
2.4 Anomaly in Measured Phase Shifts
2.5 Other Studies

3. Critical Capabilities Needed for Future Helioseismic Studies of Sunspots and Active Regions

4. Observational Requirements