How can an efficient system for Mana circulation lead to a less efficient recovery time?

Question

Witches are broken down into three classes. Class A have a limited supply of Mana, and must work in tandem with other witches to combine their power in order to pull off many spells. However, their spells can be done quickly, and their Mana recharge rate is fast. This allows them to do multiple spells a day. On the other side of the spectrum is Class C, which have a larger supply of Mana than normal. This allows them to perform powerful spells singlehandedly. However, their spells take much longer and their recovery rate is very slow. This affords them only a handful of spells a day. In the middle fall the vast majority of the population, class B, who have a general mix of both affinities.

This system is due to Mana lines within the witches body. Mana lines are similar to the ley lines crossing the planet in that they are pathways for Mana to pass through. These Mana lines run through the witch, connecting to all parts of the body. At the center is a organ that pumps the Mana through these lines. The power of a class depends on how much Mana this organ can send through this system.

Class C is far more powerful than the others because their Mana lines are expanded, allowing for more Mana to flow through them. Their special organ is larger, allowing it to pump more Mana at once. Yet even though this system is more efficient than the others, spell producing is much slower and it takes longer for their Mana to recharge, slowing the number of spells that they can perform.

How can this be the case?

Answer 1

The bigger your mana system is, the more it leaks.

We loose mana into the environment like a lake evaporating in the sun. The bigger the surface area of your lake, the more water loss over time.

A city with a really big lake for water consumption will lose more water in evaporation than a small town with a smaller lake. The same holds true if water leaks from pipes are proportional to the size and number of pipes in the water network.

Recovery rate in humans is actually basically constant (+ slight genetic / training variations). Every living human gets, say, 100 mana per hour for just being conscious.

So:

• Class A. Tiny reserve. A tiny tank, and minimal piping.
  • Can hold 30 mana in their internal tank.
  • 100 mana in per hour, 1 leaks out. Net 99 gain per hour.
  • Their mana reserve is basically filled up within 20 minutes, but they only have 30 to use.
  • 10 of them can cast a 100 mana spell 3 times instantly. And then once every 6 minutes from then on.
• Class B. Decent reserve. A medium tank, and medium piping. All this extra plumbing leaks a lot more than class A.
  • Can hold 200 mana in their internal tank.
  • 100 mana in per hour, but 20 leaks out. Net gain 80 per hour.
  • Takes them 2.5 hours to recharge.
  • Can cast 2 x 100 mana spells and then is done for a while.
• Class C. Huge reserve. Massive tank. Massive pipes. Leaks like a siv.
  • Can hold 1000 mana in their internal tank
  • 100 mana in per hour, but 70 leaks out. Net gain 30 per hour.
  • Takes them 33 hours to full recharge.
  • Can cast 10 x 100 mana spells as then is out for a few days.

To balance the group advantage towards the As, the leak rate doubles when shared with others - the pressure increases so I feel it fits.

Answer 2

Stress

Humans are incredibly resilient to stress. Both acute and long term.

Little stress gives little recovery time. A lot of stress and you'll have to relax a bit more. If you have a single huge stressful day, you'll take a lot longer to recharge. But a day or two (longer if you're older) and you might be fine from your too intense weekend rock climbing for example.

Little stress over a long time is barely noticeable, if at all. A lot of stress over time can be very dangerous. At a certain moment you'll start the day with less than 100%. But if you continue, you'll drop lower and lower, untill a point of burn out or similar. Suddenly you can't recover for weeks, months or even years.

What this shows is that "using" stress and the recovery are linked.

For mana it can work the same. You might drop the long term part, it's just an example, but linking mana recovery and usage is the important part. Using only a bit and it's easy to recover. You might even share the mana load with others, helping recovery. A huge spell can exhaust the single caster's mana capabilities, reducing the recovery until fully the mana has been replenished after a certain time.

Answer 3

Enzymes:

Your ABCs have magic that behaves like catalytic reactions of enzymes. [A] has a low threshold of activation, so the amount of mana needed to trigger a magic event is low. [C] needs a much higher level to activate magic. The activation level functions a bit like a dam, so mana leaves the caster when it exceeds the activation limit (the enzyme spontaneously activates - possibly creating magic effects). Everyone's storage limit is based on this. While powerful [c]s can do huge magics, they need huge mana to overcome the activation energy. Everyone recovers mana at the same rate, but [a]s start spontaneously losing energy they don't use, while [c]s have to be almost completely full to even use their power. [C]s also seem to take longer to recover function for this same reason.

This means your three groups can all have the same ability, just different enzymes controlling the usage. The [a] ability would be functionally dominant, as these people, even if they had the [c] gene would never reach the activation energy of the [c] or [b] ability. similarly, [b] is dominant to [c] for the same reason.

This also gives a reason you don't have huge numbers of [c] casters running around with massive magics vaporizing everything in sight, and why lesser ([a] and [b]) casters would predominate. If [a] is uniquely able to network magic among witches, this gives a reason you can't have [c]s networking - structurally, they can never have an A gene without losing the [c] phenotype.

genotype........phenotype

A/A..............[a]

A/B..............[a]

A/C..............[a]

B/B..............[b]

B/C..............[b]

C/C..............[c]

If you have a null gene in this mix, it could either be dominant (you need two genes to have magic) or recessive (so a [c] with a C/null genotype mating with a normal would get you 50% [c] children and 50% null children, and a C/C mating with a null would have all [c] kids. For something as simple as an enzyme (nature's catalysts) you could follow good old fashioned mendelian genetics.

Answer 4

Flow rate and volume capacity.

Mana webs can only be so large. But they differ in flow rate and total volume.

The mana webs of A type witches are thick, like arteries. They can accomodate rapid flow, emptying and refilling very fast. They have a limited area and also a limited volume.

The mana webs of C type witches are very thin, like a capillary bed. They empty and refill slowly. They extend over a very large area and can hold a very large volume.

B witches are in between like a venous plexus. They have a moderate refill time and a capacity between A and C.