As a Role-Play Judge, I will say that Force attacks that maintain themselves without the Force will pierce the shield.
As previously stated, throwing objects will not be affected by the bubble. This is because, just like throwing a rock with your hand, the Force is only applied for a few seconds and not all the way through the trajectory of the projectile.
Force Strength and Speed, which require roughly continuous use of the Force, will no longer work. Force Lightning will be repelled. Natural lightning will not be repelled. Use the rule above to determine if an attack would work.
A word of caution about Ysalamir, they are supposedly rare off Myrkr. They are also supposed to be difficult to transport, and the major drawback of having one on their person would be that the user would need a bulky nutrient system.
A note to Force-users that enter the Force negating bubble, though. To make this clear, absolutely no Force power can be used within it. Plus, upon exiting the people, the Force-user would experience great pain and discomfort. This is analogous to the sensation one feels when an arm or leg falls asleep due to poor blood circulation, and then the blood starts rushing back to that limb.
If you have any more questions or confusion about the Ysalamir, do not be afraid to ask.